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®
Temperature/Pressure Calibrator
525A
Service Manual
PN 1644492 March 2002
© 2002 Fluke Corporation. All rights reserved. Printed in USA All product names are trademarks of their respective companies.
LIMITED WARRANTY AND LIMITATION OF LIABILITY
Each Fluke product is warranted to be free from defects in material and workmanship under normal use and service. The warranty period is one year and begins on the date of shipment. Parts, product repairs, and services are warranted for 90 days. This warranty extends only to the original buyer or end-user customer of a Fluke authorized reseller, and does not apply to fuses, disposable batteries, or to any product which, in Fluke's opinion, has been misused, altered, neglected, contaminated, or damaged by accident or abnormal conditions of operation or handling. Fluke warrants that software will operate substantially in accordance with its functional specifications for 90 days and that it has been properly recorded on non-defective media. Fluke does not warrant that software will be error free or operate without interruption. Fluke authorized resellers shall extend this warranty on new and unused products to end-user customers only but have no authority to extend a greater or different warranty on behalf of Fluke. Warranty support is available only if product is purchased through a Fluke authorized sales outlet or Buyer has paid the applicable international price. Fluke reserves the right to invoice Buyer for importation costs of repair/replacement parts when product purchased in one country is submitted for repair in another country. Fluke's warranty obligation is limited, at Fluke's option, to refund of the purchase price, free of charge repair, or replacement of a defective product which is returned to a Fluke authorized service center within the warranty period. To obtain warranty service, contact your nearest Fluke authorized service center to obtain return authorization information, then send the product to that service center, with a description of the difficulty, postage and insurance prepaid (FOB Destination). Fluke assumes no risk for damage in transit. Following warranty repair, the product will be returned to Buyer, transportation prepaid (FOB Destination). If Fluke determines that failure was caused by neglect, misuse, contamination, alteration, accident, or abnormal condition of operation or handling, including overvoltage failures caused by use outside the product's specified rating, or normal wear and tear of mechanical components, Fluke will provide an estimate of repair costs and obtain authorization before commencing the work. Following repair, the product will be returned to the Buyer transportation prepaid and the Buyer will be billed for the repair and return transportation charges (FOB Shipping Point). THIS WARRANTY IS BUYER'S SOLE AND EXCLUSIVE REMEDY AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. FLUKE SHALL NOT BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES OR LOSSES, INCLUDING LOSS OF DATA, ARISING FROM ANY CAUSE OR THEORY. Since some countries or states do not allow limitation of the term of an implied warranty, or exclusion or limitation of incidental or consequential damages, the limitations and exclusions of this warranty may not apply to every buyer. If any provision of this Warranty is held invalid or unenforceable by a court or other decision-maker of competent jurisdiction, such holding will not affect the validity or enforceability of any other provision.
Fluke Corporation P.O. Box 9090 Everett, WA 98206-9090 U.S.A. 11/99 Fluke Europe B.V. P.O. Box 1186 5602 BD Eindhoven The Netherlands
To register your product online, visit register.fluke.com
Table of Contents
Title Introduction ....................................................................................................... Contacting Fluke ............................................................................................... Safety Information............................................................................................. Calibrator Specifications ................................................................................... General Specifications .................................................................................. DC Voltage Specifications, Output............................................................... DC Current Specifications, Output ............................................................... Resistance Specifications, Output ................................................................. Resistance Specifications, Input.................................................................... Thermocouple Specification, Output and Input ............................................ TC mV Specifications, Input and Output...................................................... RTD and Thermistor Specification, Output .................................................. RTD and Thermistor Specification, Input..................................................... Pressure Measurement .................................................................................. Theory of Operation .......................................................................................... Micro-Controller Section .............................................................................. Analog Section .............................................................................................. Basic Maintenance............................................................................................. Cleaning the Calibrator ................................................................................. Replacing a Line Fuse................................................................................... To Check or Replace a Fuse.......................................................................... Changing Line Voltage ................................................................................. Modular-Level Maintenance ............................................................................. Disassembly .................................................................................................. Reassembly ................................................................................................... Output Block Subassembly Connections.................................................. Keypad to Main PCB................................................................................ Display Assembly to Main PCB ............................................................... Opto RS232 to Main PCA ........................................................................ Reinstalling the Circuit Boards................................................................. Connecting the Power Module ................................................................. Final Assembly and Inspection ..................................................................... Performance Tests ............................................................................................. Required Equipment List .............................................................................. Testing DC Voltage.......................................................................................
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Page 1 1 1 3 3 4 4 5 5 6 7 8 9 11 11 11 12 12 12 12 13 13 14 15 15 17 19 19 20 21 21 22 23 23 24
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Service Manual
Testing DC Current ....................................................................................... Testing Thermocouple Output ...................................................................... Testing CJC (Cold Junction Compensation)............................................. CJC (Cold Junction Compensation) Calibration....................................... Testing Thermocouple Input ......................................................................... Testing Ohms Output .................................................................................... Testing Ohms Input....................................................................................... Testing Pressure Modules ............................................................................. Calibration Adjustment ..................................................................................... Initiating Communication ............................................................................. Starting Adjustment Mode ............................................................................ Adjustment Sequence.................................................................................... 14: Calibrate DAC, Digital to Analog Converter Adjustment.................. 1: 100 mV Source to 4: 100 V Source, Adjusting DC Source.................. 5: 100 mA Source, Adjusting DC Current Source.................................... 6: Hi Ohms Source, Adjusting High Resistance Source........................... 7: Low Ohms, Adjusting Low Ohms Source............................................ 8: Hi Ohms, Adjusting High Resistance Measure .................................... 9: Low Ohms, Adjusting Low Resistance Measure.................................. 10: SPRT 25, Adjusting SPRT Low Resistance Measure ........................ 11: TC SOURCE, Adjusting TC mVolt Source ....................................... 12: TC Read, Adjusting TC mVolt Measure ............................................ Customer Replaceable Parts ..............................................................................
25 26 27 27 28 29 30 32 32 32 32 33 34 34 35 37 38 38 40 41 43 43 45
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List of Tables
Table 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26.
Title Symbols Used on the Calibrator ............................................................................ Replacement Fuses ................................................................................................ Front Panel Wire Color Assignments .................................................................... Rear Panel Wire Color Assignments ..................................................................... Output Block to Main PCA Connections............................................................... TC PCA to Main PCA Connections ...................................................................... Opto RS232 to Main PCA Connections ................................................................ Power Module to Main PCA Connections............................................................. Power Connections ................................................................................................ Required Equipment .............................................................................................. Testing DC Voltage ............................................................................................... TC Temperatures ................................................................................................... Ohms Output Ranges ............................................................................................. Ohms Ratio Table .................................................................................................. Calibration Dependencies ...................................................................................... List of Equipment for Voltage Calibration Adjustments ....................................... List of Equipment for Current Calibration Adjustments ....................................... List of Equipment for High Ohms Measure Calibration Adjustments .................. List of Equipment for High Ohms Measure Calibration Adjustments .................. List of Equipment for Low Ohms Measure Calibration Adjustments ................... List of Test Equipment for Adjusting TC Source .................................................. List of Test Equipment for Adjusting TC Read..................................................... List of Test Equipment for Adjusting TC CJC ...................................................... Replacement Parts.................................................................................................. Accessories ............................................................................................................
Page 2 13 16 16 17 18 20 21 22 23 24 26 29 31 33 34 35 38 40 41 43 43 45 47 48
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525A
Service Manual
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List of Figures
Figure 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.
Title Accessing the Fuse................................................................................................. Wiring Connections ............................................................................................... Solder Connections for the TC PCA...................................................................... Keypad PCA Connections ..................................................................................... Connections for the Opto RS232 PCA .................................................................. Power Module Connections................................................................................... Measuring DC Current........................................................................................... Testing TC Output ................................................................................................. Connections for CJC Calibration ........................................................................... Connections for Measuring TC Input .................................................................... Connection for Measuring Resistance Output ....................................................... 1281 Connection Diagram ..................................................................................... Connection for Measuring Ohms........................................................................... Exploded View of the 525A ..................................................................................
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525A
Introduction
This manual provides user-service information for the 525A Temperature/Pressure Calibrator (hereafter referred to as "the Calibrator"). Details regarding verification of the Calibrator's functionality and calibration, basic maintenance, contacting Fluke service centers, and important safety information are also contained within this manual.
Contacting Fluke
To contact Fluke, order accessories, or locate the nearest Fluke Service Center or distributor, call: · · · · · · USA: 1-888-99-FLUKE (1-888-993-5853) Canada: 1-800-36-FLUKE (1-800-363-5853) Europe: +31-402-678-200 Japan: +81-3-3434-0181 Singapore: +65-738-5655 Anywhere in the world: +1-425-446-5500
Or, visit Fluke's Web site at www.fluke.com.
Safety Information
The Calibrator complies with EN 61010, ANSI/ISA-S82.01-1994, and CAN/CSA-C22.2 No. 1010.1-92. Use the Calibrator only as specified in this manual, otherwise the protection provided by the Calibrator may be impaired. CAT II equipment is designed to protect against transients from energy-consuming equipment supplied from a fixed installation, such as televisions, personal computers, portable tools, and other household appliances. A "WWarning" statement identifies hazardous conditions and actions that could cause bodily harm or death. A "WCaution" statement identifies conditions and actions that could damage the Calibrator or the equipment under test. International symbols used on the Calibrator and in this manual are explained in Table 1.
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Service Manual
WWarning
To avoid possible electric shock or personal injury, follow these guidelines: · · Use the Calibrator only as specified in this manual or the protection provided by the Calibrator might be impaired. Inspect the Calibrator before use. Do not use the Calibrator if it appears damaged. Look for cracks or missing plastic. Pay particular attention to the insulation around the connectors. Have the Calibrator serviced only by qualified service personnel. Do not apply more than the rated voltage between the terminals, as marked on the Calibrator, or between any terminal and earth ground. Always use the power cord and connector appropriate for the voltage and outlet of the country or location in which you are working. Never operate the Calibrator with the cover removed or the case open. Never remove the cover or open the case of the Calibrator without first removing the power source. Use caution when working with voltages above 30 V ac rms, 42 V ac peak, or 60 V dc. These voltages pose a shock hazard. Use only the replacement fuse(s) specified in this manual. Use the proper terminals, function, and range for your measurements. Do not operate the Calibrator around explosive gas, vapor, or dust. When servicing the Calibrator, use only specified replacement parts.
Table 1. Symbols Used on the Calibrator AC (Alternating Current) DC (Direct Current) Pressure Chassis protective ground Important Information. Refer to the manual. Caution, risk of electric shock Earth ground
· · · · · · · · ·
·
Resistance Conforms to European Union directives Canadian Standards Association, NRTL International ON/OFF symbol.
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525A Calibrator Specifications
Calibrator Specifications
General Specifications
Warm up time Settling time Standard interface Optional interface Temperature performance Twice the time since last warmed up, to a maximum of 30 minutes Less than 5 seconds for all functions and ranges except as noted RS-232 IEEE-488 (GPIB) Operating Calibration (tcal) Storage 0 °C to 50 °C 18 °C to 28 °C -20 °C to 70 °C
Electromagnetic compatibility Temperature coefficient Relative humidity Altitude Safety Analog low isolation Line power
CE: Conforms to EN61326 Temperature coefficient for temperatures outside tcal ±5 °C is 10 % of the 90 day specification (or 1 year if applicable) per °C Operating Storage < 80 % to 30 °C, < 70 % to 40 °C, < 40 % to 50 °C < 95 % noncondensing 3,050 m (10,000 ft) maximum 12,200 m (40,000 ft) maximum
Operating Nonoperating
EN 61010 Second, ANSI/ISA-S82.01-1994, CAN/CSA-C22.2 No. 1010.1-92, NRTL 20 V Line Voltage (selectable) Line Frequency Line Voltage Variation 15 VA maximum Height 13.3 cm (5.25 in) plus 1.5 cm (0.6 in) four feet on bottom Width ¾ standard rack width Depth 47.3 cm (18.6 in) overall 4 kg (9 lb) 100 V/120 V or 220 V/240 V 47 to 63 Hz ±10 % about line voltage setting
Power consumption Dimensions
Weight (without options)
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Service Manual
DC Voltage Specifications, Output
Absolute Uncertainty, tcal ±5 °C
± (ppm of output +µV)
Stability 24 hours, ±1 °C
± (ppm of output +µV)
Ranges1 0 to 100.000 mV 0 to 1.00000 V 0 to 10.0000 V 0 to 100.000 V
90 days 25 25 25 25 3 20 200 2 mV 30 30 30 30
1 year 3 20 200 2 mV
Resolution 1 µV 10 µV 100 µV 1 mV
Maximum Burden2 10 mA 10 mA 10 mA 1 mA
5 +2 4 +20 4 +200 5 +1 mV
1. All outputs are positive only. 2. Remote sensing is not provided. Output resistance is < 1.
Noise Ranges 0 to 100.000 mV 0 to 1.00000 V 0 to 10.0000 V 0 to 100.000 V Bandwidth 0.1 to 10 Hz (ppm of output +µV p-p) 1 µV 10 µV 100 µV 10 ppm+1 mV Bandwidth10 Hz to 10 kHz (µV rms) 6 µV 60 µV 600 µV 20 mV
DC Current Specifications, Output
Absolute Uncertainty, tcal ±5 °C ± (ppm of output +µA) Ranges1 0 to 100.000 mA 90 days 85 2 1 year 100 2 Resolution 1 µA Maximum Compliance Voltage 10 V Maximum Inductive Load 100 µH
1. All outputs are positive only.
Noise Ranges 0 to 100.000 mA Bandwidth 0.1 to 10 Hz p-p 2000 nA Bandwidth 10 Hz to 10 kHz rms 20 µA
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525A Calibrator Specifications
Resistance Specifications, Output
Absolute Uncertainty, tcal ±5 °C, ±(ppm of output ± ) Ranges1 90 days 5 to 400.00 5 to 4.0000 k 1. 2. 0.025 0.25 1 year 0.03 0.3 0.01 0.1 1 to 10 mA 250 µA to 1 mA Resolution Allowable Current2
Continuously variable from 0 to 4 k. For currents lower than shown, the floor adder increases by Floor(new) = Floor(old) x Imin/Iactual. For example, a 500 µA stimulus measuring 100 has a floor uncertainty of 0.025 x 1 mA/500 µA = 0.05 .
Resistance Specifications, Input
Absolute Uncertainty, tcal ±5 °C, ±(ppm of output ± ) Ranges 0 to 400.00 401 to 4001.00 35 35 90 days 0.003 0.03 40 40 1 year 0.003 0.03 Resolution 0.001 0.01 Stimulus Current 1 mA 0.1 mA
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Thermocouple Specification, Output and Input
Absolute Uncertainty, tcal ±5 °C, ±(°C)1 Range (°C) TC Type B Minimum 600 °C 800 °C 1000 °C 1550 °C 0 °C 150 °C 650 °C 1000 °C 1800 °C -250 °C -100 °C -25 °C 350 °C 650 °C -210 °C -100 °C -30 °C 150 °C 760 °C -200 °C -100 °C -25 °C 120 °C 1000 °C -200 °C -100 °C 800 °C -200 °C -100 °C -25 °C 120 °C 410 °C Maximum 800 °C 1000 °C 1550 °C 1820 °C 150 °C 650 °C 1000 °C 1800 °C 2316 °C -100 °C -25 °C 350 °C 650 °C 1000 °C -100 °C -30 °C 150 °C 760 °C 1200 °C -100 °C -25 °C 120 °C 1000 °C 1372 °C -100 °C 800 °C 900 °C -100 °C -25 °C 120 °C 410 °C 1300 °C 90 days 0.42 °C 0.39 °C 0.40 °C 0.44 °C 0.25 °C 0.21 °C 0.23 °C 0.38 °C 0.63 °C 0.38 °C 0.16 °C 0.14 °C 0.14 °C 0.16 °C 0.20 °C 0.18 °C 0.14 °C 0.14 °C 0.18 °C 0.25 °C 0.19 °C 0.14 °C 0.19 °C 0.30 °C 0.37 °C 0.26 °C 0.17 °C 0.33 °C 0.20 °C 0.16 °C 0.14 °C 0.21 °C Output/Input 1 year 0.46 °C 0.39 °C 0.40 °C 0.45 °C 0.30 °C 0.26 °C 0.31 °C 0.50 °C 0.84 °C 0.50 °C 0.18 °C 0.15 °C 0.16 °C 0.21 °C 0.27 °C 0.20 °C 0.16 °C 0.17 °C 0.23 °C 0.33 °C 0.22 °C 0.16 °C 0.26 °C 0.40 °C 0.37 °C 0.26 °C 0.17 °C 0.40 °C 0.24 °C 0.19 °C 0.18 °C 0.27 °C
C
E
J
K
L
N
1. Does not include thermocouple wire error.
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525A Calibrator Specifications
Thermocouple Specification, Output and Input (continued)
Absolute Uncertainty, tcal ±5 °C, ±(°C)1 Range (°C) TC Type R Minimum 0 °C 250 °C 400 °C 1000 °C 0 °C 250 °C 1000 °C 1400 °C -250 °C -150 °C 0 °C 120 °C -200 °C 0 °C -10 to 75.000 mV Maximum 250 °C 400 °C 1000 °C 1750 °C 250 °C 1000 °C 1400 °C 1750 °C -150 °C 0 °C 120 °C 400 °C 0 °C 600 °C Output/Input 90 days 0.58 °C 0.34 °C 0.31 °C 0.30 °C 0.56 °C 0.36 °C 0.30 °C 0.35 °C 0.51 °C 0.18 °C 0.13 °C 0.12 °C 0.56 °C 0.27 °C 1 year 0.58 °C 0.35 °C 0.33 °C 0.40 °C 0.56 °C 0.36 °C 0.37 °C 0.46 °C 0.63 °C 0.24 °C 0.16 °C 0.14 °C 0.56 °C 0.27 °C
S
T
U mV
1. Does not include thermocouple wire error.
TC mV Specifications, Input and Output
Absolute Uncertainty, tcal +/-5 °C +/-( ppm of output + µV) Range (mV) -10 to 75.000 90 Days 25 + 3µV 1 Year 30 + 3µV
Stability 24 Hours +/-1°C +/- ( ppm of output + µV) 5 + 2µV
Resolution 1µV
Maximum Burden 10 Ohms
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Service Manual
RTD and Thermistor Specification, Output
Range (°C) RTD Type Pt 385, 100 Minimum -200 °C -80 °C 0 °C 100 °C 300 °C 400 °C 630 °C -200 °C -80 °C 0 °C 100 °C 300 °C 400 °C -200 °C -190 °C -80 °C 0 °C 100 °C 260 °C 300 °C 400 °C 600 °C -200 °C -80 °C 0 °C 100 °C 260 °C 300 °C 400 °C 600 °C -200 °C -80 °C 0 °C 100 °C 260 °C 300 °C 400 °C 600 °C Maximum -80 °C 0 °C 100 °C 300 °C 400 °C 630 °C 800 °C -80 °C 0 °C 100 °C 300 °C 400 °C 630 °C -190 °C -80 °C 0 °C 100 °C 260 °C 300 °C 400 °C 600 °C 630 °C -80 °C 0 °C 100 °C 260 °C 300 °C 400 °C 600 °C 630 °C -80 °C 0 °C 100 °C 260 °C 300 °C 400 °C 600 °C 630 °C Absolute Uncertainty tcal ±5 °C, ±(°C)1 90 days 0.06 °C 0.08 °C 0.08 °C 0.07 °C 0.07 °C 0.08 °C 0.08 °C 0.06 °C 0.06 °C 0.06 °C 0.07 °C 0.07 °C 0.08 °C 0.06 °C 0.06 °C 0.06 °C 0.06 °C 0.07 °C 0.07 °C 0.07 °C 0.08 °C 0.08 °C 0.31 °C 0.32 °C 0.33 °C 0.33 °C 0.36 °C 0.36 °C 0.42 °C 0.42 °C 0.13 °C 0.13 °C 0.13 °C 0.14 °C 0.14 °C 0.15 °C 0.16 °C 0.16 °C 1 year 0.07 °C 0.10 °C 0.10 °C 0.09 °C 0.09 °C 0.09 °C 0.10 °C 0.07 °C 0.07 °C 0.08 °C 0.08 °C 0.09 °C 0.09 °C 0.07 °C 0.08 °C 0.08 °C 0.08 °C 0.08 °C 0.08 °C 0.09 °C 0.09 °C 0.09 °C 0.38 °C 0.38 °C 0.39 °C 0.39 °C 0.43 °C 0.43 °C 0.50 °C 0.50 °C 0.15 °C 0.15 °C 0.16 °C 0.17 °C 0.17 °C 0.18 °C 0.19 °C 0.19 °C
Pt 3926, 100
Pt 3916, 100
Pt 385, 200
Pt 385, 500
1. 2-wire output
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525A Calibrator Specifications
RTD and Thermistor Specification, Output (continued)
Range (°C) RTD Type Pt 385, 1000 Minimum -200 °C -80 °C 0 °C 100 °C 260 °C 300 °C 400 °C 600 °C -80 °C 0 °C 100 °C -100 °C 15 °C Maximum -80 °C 0 °C 100 °C 260 °C 300 °C 400 °C 600 °C 630 °C 0 °C 100 °C 260 °C 260 °C 50 °C Absolute Uncertainty tcal ±5 °C, ±(°C)1 90 days 0.06 °C 0.06 °C 0.07 °C 0.07 °C 0.07 °C 0.07 °C 0.08 °C 0.08 °C 0.04 °C 0.04 °C 0.03 °C 0.63 °C 0.005 °C 1 year 0.07 °C 0.08 °C 0.08 °C 0.08 °C 0.09 °C 0.09 °C 0.09 °C 0.09 °C 0.05 °C 0.04 °C 0.03 °C 0.75 °C 0.007 °C
PtNi 385, 120 (Ni 120) Cu 427, 10 2 YSI 400 1. 2-wire output
2. Based on MINCO Application Aid No. 18.
RTD and Thermistor Specification, Input
Range (°C) RTD Type Pt 385, 100 Minimum -200 °C -80 °C 0 °C 100 °C 300 °C 400 °C 630 °C -200 °C -80 °C 0 °C 100 °C 300 °C 400 °C -200 °C -190 °C -80 °C 0 °C 100 °C 260 °C 300 °C 400 °C 600 °C -200 °C -80 °C 0 °C 100 °C 260 °C 300 °C 400 °C 600 °C Maximum -80 °C 0 °C 100 °C 300 °C 400 °C 630 °C 800 °C -80 °C 0 °C 100 °C 300 °C 400 °C 630 °C -190 °C -80 °C 0 °C 100 °C 260 °C 300 °C 400 °C 600 °C 630 °C -80 °C 0 °C 100 °C 260 °C 300 °C 400 °C 600 °C 630 °C Absolute Uncertainty, tcal ±5 °C, ±(°C)1 90 days 0.031 °C 0.018 °C 0.018 °C 0.027 °C 0.031 °C 0.042 °C 0.050 °C 0.031 °C 0.014 °C 0.018 °C 0.026 °C 0.031 °C 0.041 °C 0.026 °C 0.011 °C 0.014 °C 0.018 °C 0.025 °C 0.026 °C 0.031 °C 0.040 °C 0.042 °C 0.071 °C 0.075 °C 0.079 °C 0.082 °C 0.090 °C 0.093 °C 0.100 °C 0.101 °C 1 year 0.012 °C 0.020 °C 0.020 °C 0.030 °C 0.035 °C 0.047 °C 0.057 °C 0.031 °C 0.015 °C 0.019 °C 0.029 °C 0.034 °C 0.046 °C 0.028 °C 0.012 °C 0.015 °C 0.019 °C 0.028 °C 0.029 °C 0.034 °C 0.045 °C 0.047 °C 0.072 °C 0.076 °C 0.081 °C 0.085 °C 0.093 °C 0.097 °C 0.105 °C 0.106 °C
Pt 3926, 100
Pt 3916, 100
Pt 385, 200
1. 4-wire mode. Uncertainties listed do not include probe uncertainties.
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Service Manual
RTD and Thermistor Specification, Input (continued)
Range (°C) RTD Type Pt 385, 500 Minimum -200 °C -80 °C 0 °C 100 °C 260 °C 300 °C 400 °C 600 °C -200 °C -80 °C 0 °C 100 °C 260 °C 300 °C 400 °C 600 °C -80 °C 0 °C 100 °C -100 °C 15 °C User Defined Maximum -80 °C 0 °C 100 °C 260 °C 300 °C 400 °C 600 °C 630 °C -80 °C 0 °C 100 °C 260 °C 300 °C 400 °C 600 °C 630 °C 0 °C 100 °C 260 °C 260 °C 50 °C User Defined Absolute Uncertainty, tcal ±5 °C, ±(°C)1 90 days 0.046 °C 0.049 °C 0.043 °C 0.030 °C 0.032 °C 0.037 °C 0.047 °C 0.048 °C 0.031 °C 0.034 °C 0.039 °C 0.025 °C 0.027 °C 0.030 °C 0.041 °C 0.042 °C 0.209 °C 0.210 °C 0.211 °C 0.300 °C 0.005 °C 0.05 °C 1 year 0.047 °C 0.050 °C 0.045 °C 0.033 °C 0.035 °C 0.041 °C 0.052 °C 0.076 °C 0.032 °C 0.035 °C 0.040 °C 0.028 °C 0.030 °C 0.034 °C 0.045 °C 0.047 °C 0.210 °C 0.211 °C 0.212 °C 0.069 °C 0.304 °C 0.06 °C
Pt 385, 1000
PtNi 385, 120 (Ni120) Cu 427, 10 2 YSI 400 SPRT, 25
1. 4-wire mode. Uncertainties listed do not include probe uncertainties. 2. Based on MINCO Application Aid No. 18.
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525A Theory of Operation
Pressure Measurement The Calibrator can accept either the Fluke 700 or 6100 series pressure modules. Pressure modules plug directly into the front panel Lemo connector. The Calibrator firmware automatically detects the type and value of the module you are attaching, and recognizes the following units of measurement:
· · · · · · · · · · PSI (pounds per square inch) inH2O4°C (inches of water at 4 degrees Celsius) inH2O20C (inches of water at 20 degrees Celsius) cmH2O4°C (centimeters of water at 4 degrees Celsius) cmH2O20C (centimeters of water at 20 degrees Celsius) BAR (bars) mBAR (millibars) KPAL (kilopascals) inHG 0°C (inches of mercury at 0 degrees Celsius) mmHG 0°C (millimeters of mercury at 0 degrees Celsius) Kg/cm2 (kilograms per square centimeter)
·
Theory of Operation
The Calibrator serves as an accurate laboratory device for calibrating thermocouples, RTDs, pressure devices, and low-level dc voltages and currents. The main PCB assembly, and several subassemblies, work together to provide high-reliability and easy maintenance.
Micro-Controller Section The Atmel ATmega 103 micro-controller is the heart of the 525A. It contains all of the program memory, nv-ram, FlashROM, static RAM, and EEProm. The micro-controller allows a minimal amount of external glue logic. The main external digital ICs are the RS232 driver, relay drivers, LCD controller, and the digitally controlled analog switches. Many of the ICs are interfaced through the micro-controller's three-wire SPI bus minimizing interconnecting lines. Inputs or outputs begin with instructions entered through the keypad or through remote communications (serial or IEEE-488) into the micro-controller. The micro-controller processes the commands and sets conditions that are appropriate for the command.
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Service Manual
Analog Section The Calibrator can source DC voltage to 100 V, DC current to 100 mA, resistances from 5 to 4000 , and thermocouples and RTDs. The main components of the analog circuit consist of a precision 2.5-volt temperature compensated reference, 20-bit DAC and a 24-bit ADC. Precision metal foil resistor networks and several chopper-stabilized OP-AMPS are the most critical analog components.
When sourcing, the micro-controller, using stored calibration constants, adjusts the D/A to generate an output based on the function and range selected. To achieve high accuracy, a low drift 24-bit A/D converter is used as a feedback element near the output of the D/A converter. The scaled output DAC_CK is routed to the A/D converter. In the input mode, the A/D is used directly to measure either the T/C or the resistance (RTD) inputs. The A/D features an internal self-calibration function that continually nulls out zero drift due to temperature changes. A programmable gain stage in the A/D is adjusted by the microcontroller to allow direct T/C and RTD inputs without requiring external amplification. In the RTD mode, a constant current source is used to excite the RTD and the voltage developed across the RTD is measured by the A/D, then the resistance can be calculated.
Basic Maintenance
W Warning
To avoid personal injury or damage to the Calibrator, use only the specified replacement parts and do not allow water into the case.
Cleaning the Calibrator
WCaution
To avoid damaging the case, do not use solvents or abrasive cleaners. Clean the Calibrator and pressure modules with a soft cloth dampened with water or mild soap and water.
Replacing a Line Fuse
W Warning
To avoid electrical shock, disconnect line power before opening the case or line voltage selector. The line power fuses and line voltage selector switch are located in a compartment above the power switch on the right rear of the Calibrator. The fuse-rating label on the rear panel shows the correct replacement fuse for each line voltage setting. Table 2 lists the fuse part numbers for each line voltage setting. Figure 1 shows how to remove the fuse compartment cover.
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525A Basic Maintenance
To Check or Replace a Fuse 1. Disconnect line power.
2. Using a flat-blade screwdriver, pry the tab at the base of the line fuse compartment. The compartment cover will pop part way out. 3. Remove the compartment cover. The fuses come out with the compartment cover and can easily be checked or replaced. 4. To reinstall the fuse, push the compartment cover back into the compartment until the tab locks in place. Note When changing the line voltage setting, make sure to verify that the appropriate line fuse is installed in the Calibrator. Replace the fuse as required.
Table 2. Replacement Fuses Part Number 1645311 1645327 Fuse Description W Fuse, 0.25 A fast fuse W Fuse, 0.125 A fast fuse Line Voltage Setting 120 V (90 V to 132 V) 240 V (198 V to 264 V)
Changing Line Voltage The Calibrator arrives from the factory configured for the line voltage appropriate for the country of purchase or as specified when it is ordered. To verify the line voltage setting, check the line voltage indicator on the line power fuse compartment cover.
Note Confirm that the line voltage selection is set for 120 V for line voltages between 90 V and 132 V or that the selector is set to 240 V for line voltages between 198 V and 264 V. To change the line voltage: 1. Disconnect line power. 2. Using a flat-blade screwdriver, pry the tab at the base of the line fuse compartment. The compartment cover will pop part way out. 3. Remove the compartment cover. 4. Remove the line voltage selector assembly by gripping the line voltage indicator tab with pliers and pulling it straight out of the compartment. 5. Rotate the line voltage selector assembly to the desired voltage and reinsert. 6. Verify the appropriate fuse is being used for the selected line voltage (see Table 2) and reinstall the fuse compartment by pushing it in until the tab locks in place.
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Service Manual
Line voltage indicator
Changing line fuse
Line fuse compartment
120V
Rotate to change line voltage indicator
0V (SB)
Changing line voltage
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Figure 1. Accessing the Fuse
Modular-Level Maintenance
XWarning
Do not attempt to complete the following procedures unless qualified to do so. This information is for use by qualified personnel only. WCaution When making solder connections, use "no clean" solder. At some point in time, it may be necessary to perform modular-level maintenance or troubleshooting of the Calibrator.
14
240V
120
525A Modular-Level Maintenance
Evaluation of most problems can be made after the top cover is removed. Inside the chassis are six circuit boards. They are connected to one another with point to point wiring. The six circuit boards are the Main PCA, Keypad PCA, TC PCA, Lemo PCA, Opto RS232 PCA, and the Display PCA. Most of the Calibrator circuitry is located on the Main PCA. The Display PCA, Keypad PCA, and Lemo PCA are mounted to the front of the chassis. The TC PCA is mounted in the Output Block, and the Opto RS232 PCA is mounted on the rear of the chassis. If the Main PCA needs repair, it is recommended that all other circuit boards be removed from the chassis still assembled. Repair of the other circuit boards can be accomplished while leaving them inside the chassis.
Disassembly To open the Calibrator case, remove the six screws from each end and lift off the top cover.
To remove all of the circuit boards while still assembled, do the following: 1. Stand the chassis on the front handles. 2. Remove the four nylon screws that attach the Display PCA to the front. 3. Remove the six screws that attach the Keypad PCA to the front. 4. Remove the five nuts that attach the Output Block to the front. 5. Remove the standoff nuts from the 9-pin D connector on the Opto RS232 PCA, if present. 6. Stand the 525A back on its feet. 7. Remove the screws attaching the Opto RS232 PCA to the back, if present. 8. Remove the four screws through the transformer. 9. Remove the six screws that attach the Main PCA to the chassis base. 10. Carefully lift all of the attached circuit boards out of the chassis.
Reassembly It is easier to solder the wires interconnecting the circuit boards before placing the assemblies back into the chassis. The procedures in this section will explain how to reconnect each of the circuit boards.
There are two wire sets available from Fluke. These wire sets are used to connect the circuit boards. One set is for the front connections and the other set is for the rear panel connections. Refer to Figure 2 for wire locations and Tables 3 and 4 for the detailed list of front and rear panel connections.
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Service Manual
Table 3. Front Panel Wire Color Assignments Gage (all lengths are 6 inches) 24 g Wire 24 g Wire 20 g Wire * 20 g Wire * 20 g Wire * 20 g Wire * 20 g Wire * 20 g Wire * 20 g Wire * 20 g Wire * 20 g Wire * 20 g Wire * 20 g Wire *
Wire Number J5 J7 J16 J 17 J18 (1st 6 inches) J19 J20 J21 J22 (2nd six inches) J33 J34 J35 J36 * Connect With Terminal Lug Red Black Purple Grey Red Black Blue Yellow Red White/Red Green White Black/Red
Color
Table 4. Rear Panel Wire Color Assignments Gage (all lengths are 6 inches) 20 g Wire* 20 g Wire* 20 g Wire * 20 g Wire * 20 g Wire * 20 g Wire *
Wire Number AC3 AC4 AC7 AC8 AC9 AC10 * Connect With Spade Lug Red White Red Green Black White
Color
16
525A Modular-Level Maintenance
Ribbon wire
Purple wire Yellow wire Blue wire Red wire
Yellow wire
Blue wire
Grey wire Purple wire
Red wires
Green wire
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Figure 2. Wiring Connections
Output Block Subassembly Connections Table 5 lists the connections to be made when connecting the Output Block to the Main PCA. Use 8-32 low thermal nuts and 8-32 low thermal washers for these connections.
Table 5. Output Block to Main PCA Connections Wire Color Blue Yellow Purple Grey Green White Red (2 wires) Black Black with red stripe White with red stripe J20 J21 J16 J17 J34 J35 J18 & J22 one leg of the 0.1 µF Cap J19 the other leg of the 0.1 µF Cap J33 J36 Connect From RTD HI RTD LO mA HI mA LO 4 W RTD Sense HI 4 W RTD Sense LO Volts Hi Volts LO 4 W RTD HI 4 W RTD LO Connect To
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Service Manual
The TC PCA needs to be connected to the Main PCA. Use the wire connections listed in Table 6. These connections require soldering. Refer to Figure 3.
Table 6. TC PCA to Main PCA Connections Solder From TC PCA (from left to right) 1st wire pad 2nd wire pad 3rd wire pad 4th wire pad 5th wire pad 6th wire pad J23 J24 J25 J26 J27 J28
Wire Color Red Black Blue Yellow White Purple
Solder To Main PCA
Blue wire Red wire Yellow wire Purple wire
Ribbon cable
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Figure 3. Solder Connections for the TC PCA
18
525A Modular-Level Maintenance
Keypad PCA to Main PCA To connect the Keypad PCA to the Main PCA, solder the following connections (refer to Figure 4):
1. Solder the 12-conductor cable to the back of the Keypad PCA with pin 1 on the cable aligned with pin 1 on the Keypad PCA. 2. Solder the Keypad ribbon cable to J11 with pin 1 lined up with the square hole in J11.
Ribbon cables
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Figure 4. Keypad PCA Connections
Display Assembly to Main PCA To attach the Display Assembly to the Main PCA, make the following connections:
1. Solder a red wire from J5 on the Main PCA to the "A" hole in the Display PCA. 2. Solder a black wire from J7 on the Main PCA to the "K" hole in the Display PCA. 3. Solder the 14-connector cable to the back of the Display PCA with pin 1 on the cable aligned with pin 1 on the Display PCA. 4. Solder the 14-conductor ribbon cable to the LCD Display (J4) position on the right side of the Main PCA with pin 1 in the square hole in J4.
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Service Manual
Opto RS232 PCA to Main PCA Use 4 wires to connect the Opto RS232 PCA to the Main PCA. Refer to Table 7 and Figure 5.
Table 7. Opto RS232 to Main PCA Connections Main PCA J38, pin 2 J38, pin 3 J38, pin 5 J63 J1, pin 2 J1, pin 3 J1, pin 5 J1, pin 4 Opto RS232
After completing this task, the circuit board assembly is ready to reinstall into the chassis.
Red wire
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Figure 5. Connections for the Opto RS232 PCA
20
525A Modular-Level Maintenance
Reinstalling the Circuit Boards 1. Place the Main PCA with all its attachments into the chassis base. 2. Put the Output Block into place in the front of the chassis.
3. Use five nylock nuts to secure the Output Block to the Chassis Base. 4. Lay the Main PCA down so that it is in place. 5. Use the (6) 6-32 5/8" screws and (6) lock washers to secure the Main PCA to the chassis base. 6. Use the (4) 6-32 X-former screws and (4) #6 nylon washers to secure the transformer to the chassis. 7. Using the (2) jack standoffs, attach the Opto RS232 PCA to the rear of the chassis. 8. Stand the unit on its front handles. 9. Insert the keypad into the front of the chassis. 10. Use (6) 6-32 x 3/8" screws to attach the Keypad PCA to the chassis base. 11. Remove the protective plastic from the LCD and put it over the lens on the front label (outside). 12. Use the (4) 6-32 nylon screws and the 4 nylon washers to attach the Display PCA to the chassis. The washers go between the Display PCA and the chassis base.
Connecting the Power Module To attach the Power Module to the Main PCA, make the connections listed in Table 8. Refer to Figure 6.
Table 8. Power Module to Main PCA Connections Wire Color Red White Red Green Black White AC3 AC4 AC7 AC8 AC9 AC10 From To Terminal 3 on Power Module Terminal 4 on Power Module Terminal 7 on Power Module Terminal 8 on Power Module Terminal 9 on Power Module Terminal 10 on Power Module
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Service Manual
Red wires
Green wire
Top view
Red wires
Green wire
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Figure 6. Power Module Connections
Final Assembly and Inspection To complete final assembly and inspection, use a digital multimeter and verify the continuity of the connections listed in Table 9.
Table 9. Power Connections Wire Color Red White Red Green Black White Red Black White N/A Position B Power Module Pin 3 Power Module Pin 4 Power Module Pin 7 Power Module Pin 8 Power Module Pin 9 Power Module Pin 10 J5 J7 J62 J52 AC3 AC4 AC7 AC8 AC9 AC10 LCD J2 A LCD J2 K Opto Pin 4 Inside Chassis Base (no connection) Position on Main PCA
Install tie wraps around the AC wires, the Output Block wires, the LCD backlight wires, the 5-conductor cable, and the Opto-RS232 wires.
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525A Performance Tests
Performance Tests
The following performance tests are used to verify the functionality of the Calibrator. If the Calibrator fails any part of the performance tests, calibration adjustment or repair by a Fluke Service Center is in order. For a list of service centers, refer to "Contacting Fluke" earlier in this manual.
Required Equipment List To complete the performance tests and calibration adjustment, the equipment listed in Table 10 is necessary. If the equipment listed is not available, equipment with the same or better specifications can be substituted.
Table 10. Required Equipment Manufacturer Fluke Fluke Fluke Fluke Fluke Model Fluke- 525A/Leads 742A-10 742A-100 742A-10K 5520A Equipment Test Lead Set Resistance Standard, 10 Resistance Standard, 100 Resistance Standard, 10K Calibrator All Functions 100 mA source calibration Low Ohms Measure and SPRT Calibration. Hi Ohms Measure Calibration Low Ohms Measure and SPRT Calibration. Hi Ohms Measure Calibration. All functions except CJC Low Ohms Measure and SPRT Calibration. Hi Ohms Measure Calibration. TC CJC Calibration TC CJC Calibration TC CJC Calibration TC CJC Calibration TC tests TC tests Purpose
Wavetek _
1281 _
DMM Ohms Shorting Block RTD Probe Precision Thermometer J Thermocouple Probe
_ Hart Scientific Omega _ _ _
_ 1521
_ _ _
Lag Bath Dewar Flask with lid Banana Jack to Copper TC MiniConnector Cable
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Service Manual
Testing DC Voltage The DC voltage amplitude accuracy test verifies the accuracy of DC voltage at the 525A calibrator front panel Volts Source output. See Table 11.
Table 11. Testing DC Voltage Nominal Value (V) 0 0.025 0.075 0.1 1.0 V 0 0.25 0.75 1 10.0 V 0 2.5 7.5 10 100.0 V 0 25 75 100 Measured Value 90 Day Spec. (V) 0.000003 3.63E-06 4.88E-06 5.5E-06 0.00002 2.63E-05 3.88E-05 0.000045 0.0002 0.000263 0.000388 0.00045 0.002 0.002625 0.003875 0.0045 One Year Spec. (V) 0.000003 3.75E-06 5.25E-06 0.000006 0.00002 2.75E-05 4.25E-05 0.00005 0.0002 0.000275 0.000425 0.0005 0.002 0.00275 0.00425 0.005
Range 100 mV
Deviation %
24
525A Performance Tests
Testing DC Current Use the Wavetek 1281 and the precision shunt to measure the 525A output as shown in Figure 7. Take the Voltage reading from the Wavetek 1281 and divide it by the 742A-1 actual value. See Table 12.
525A
525A TEMPERATURE / PRESSURE CALIBRATOR
Current Shunt
VOLTS
mA
100mA MAX
RTD
HI
OUTPUT
100V MAX
HI
STBY OPR VOLTS mA TC RTD TYPE UNITS
LO
20V PK MAX
LO
TC
INPUT/OUTPUT
OUTPUT
INPUT
ZERO
7
4W RTD
SETUP
8
CJC
9
C/ F
SHIFT
4
HI
INPUT SENSE
20V PK MAX
5
RECALL
6
AUTOSET
1281 DCV Function
CE
SET
1
RNG LOCK
2
LOCAL
3
EXP
LO
20V PK MAX
/
0
·
ENTER
mA Output Terminals
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Figure 7. Measuring DC Current
Table 12. Measuring DC Current 742A-1 Shunt Value Direct Into 1281 Input
100 mA Output (A) 0.000 0.025 0.075 0.100
Volt
Current (I=E/R)
90 Day (A) 0.000002 0.0000041 0.0000083 0.0000105
1 Year (A) 0.000002 0.0000045 0.0000095 0.000012
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Service Manual
Testing Thermocouple Output For this test the TC mV specifications will be used. When this test is combined with the CJC test, all functions of the TC output will have been checked. Typically, the cable needs to connect the 525A to the 1281 and will need to be fabricated. The TC miniconnector will need to be copper - copper (white). Using copper wire, connect the TC mini-connector to standard banana jacks. See Figure 8 for a connection diagram.
For this test, the CJC (cold junction compensation) must be turned off. Press I 5 to turn off the CJC. XCJC on the display indicates that the CJC is turned off. Select TC, and Output. Press Euntil mV/°C is shown on the display. Output the mV values listed in Table 13.
525A
525A TEMPERATURE / PRESSURE CALIBRATOR
VOLTS
mA
100mA MAX
RTD
HI
OUTPUT
100V MAX
HI
STBY OPR VOLTS mA TC RTD TYPE UNITS
LO
20V PK MAX
LO
TC
INPUT/OUTPUT
OUTPUT
INPUT
ZERO
7
4W RTD
SETUP
8
CJC
9
C/ F
SHIFT
4
HI
INPUT SENSE
20V PK MAX
5
RECALL
6
AUTOSET
SET
1
RNG LOCK
2
LOCAL
3
EXP
LO
20V PK MAX
/
0
·
ENTER
CE
1281
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Figure 8. Testing TC Output
Table 13. TC Temperatures Nominal Voltage (mV) -5.000 15.00 30.00 50.00 70.00 90 Day Spec. (mV) 0.003125 0.003375 0.00375 0.00425 0.00475 1 Year Spec. (mV) 0.00315 0.00345 0.0039 0.0045 0.0051
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525A Performance Tests
Testing CJC (Cold Junction Compensation) Connect a Type-J thermocouple to the TC terminal on the 525A. Immerse the thermocouple and a precision thermometer into a mineral oil lag bath. The test set-up is shown in Figure 9.
Verify that the readings of the 525A and the precision thermometer are within the Type-J specifications: · · The 90 day spec is 0.14 °C The 1 year spec is 0.16 °C Note Typical Type-J thermocouples Do not have specifications accurate enough to be used as a standard. To maintain a good Test Uncertainty Ratio (TUR) a characterized Type-J thermocouple may need to be used.
CJC (Cold Junction Compensation) Calibration Connect a Type-J thermocouple to the TC terminals on the Calibrator, and immerse the thermocouple and a precision thermometer in a mineral oil lag bath. The test setup is shown in Figure 9. Verify that the readings of the thermometer and the Calibrator are within the thermocouple specifications listed in the Specifications section.
Mercury Thermometer
525A
525A TEMPERATURE / PRESSURE CALIBRATOR
VOLTS
mA
100mA MAX
RTD
HI
OUTPUT
100V MAX
HI
STBY OPR VOLTS mA TC RTD TYPE UNITS
LO
20V PK MAX
LO
TC
INPUT/OUTPUT
OUTPUT
INPUT
ZERO
7
4W RTD
SETUP
8
CJC
9
C/ F
SHIFT
4
HI
INPUT SENSE
20V PK MAX
5
RECALL
6
AUTOSET
SET
1
RNG LOCK
2
LOCAL
3
EXP
LO
20V PK MAX
/
0
·
ENTER
CE
J type Thermocouple Mineral Oil Lag Bath
Dewar Flask and Cap
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Figure 9. Connections for CJC Calibration
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Service Manual
Testing Thermocouple Input Set the 525A to TC input by pressing I then 7. All other 525A conditions will be the same as the thermocouple output test, CJC off, mV/°C mode.
Connect the 525A to the 5520A as shown in Figure 10. Set the 5520A to output the mV values in Table 13.
525A
525A
TEMPERATURE / PRESSURE CALIBRATOR
VOLTS
mA
100mA MAX
RTD
HI
OUTPUT
100V MAX
HI
STBY OPR VOLTS mA TC RTD TYPE UNITS
LO
20V PK MAX
LO
TC
INPUT/OUTPUT
OUTPUT
INPUT
ZERO
7
4W RTD
SETUP
8
CJC
9
C/ F
SHIFT
4
HI
INPUT SENSE
20V PK MAX
5
RECALL
6
AUTOSET
SET
1
RNG LOCK
2
LOCAL
3
EXP
LO
20V PK MAX
/
0
·
ENTER
CE
5520A Normal Output DC Volts Function
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Figure 10. Connections for Measuring TC Input
28
525A Performance Tests
Testing Ohms Output Use the precision digital multimeter (DMM) to measure the resistance output. Figure 11 shows the four-wire connections. See Table 14.
Note The Wavetek 1281 must be in the "loI" (low current mode) when measuring 5 in the 4 k range or an overload will occur.
525A
525A TEMPERATURE / PRESSURE CALIBRATOR
VOLTS
mA
100mA MAX
RTD
HI
OUTPUT
100V MAX
HI
STBY OPR VOLTS mA TC RTD TYPE UNITS
LO
20V PK MAX
LO
TC
INPUT/OUTPUT
OUTPUT
INPUT
ZERO
7
4W RTD
SETUP
8
CJC
9
C/ F
SHIFT
4
HI
INPUT SENSE
20V PK MAX
5
RECALL
6
AUTOSET
1281 Ohms 4-wire Function
CE
SET
1
RNG LOCK
2
LOCAL
3
EXP
LO
20V PK MAX
/
0
·
ENTER
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Figure 11. Connection for Measuring Resistance Output
Table 14. Ohms Output Ranges Range () 400 5 100 200 300 400 4000 5 1000 2000 3000 4000 0.3 0.3 0.3 0.03 0.03 0.03 0.3 Output () 0.03 1 Year ()
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Testing Ohms Input Before measuring ohms input, the ohms output of a 5520A must be "characterized". To achieve the needed accuracy, the Wavetek 1281 is used as a transfer standard and the 742A is used as the reference standard. To find the true value of the 5520A output, the ratio-input function of the Wavetek 1281 is used. The ratio function of the 1281 is located on the rear panel and is designated as Channel A and Channel B. Connect Channel A to the 742A and connect the 5520A to Channel B, both using four-wire measure. See Figure 12 for a connection diagram.
1281
Chan A
31 28 23 21
Rear inputs
Chan B
31 28 23 21
Pin
Pin
Hi
I+
I-
Lo
Hi
I+
I-
Lo
742
5520A
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Figure 12. 1281 Connection Diagram
For the 400 range use the 742A-1K and for the 4 k range use the 742A-10K. For more information on the correct usage of ratio mode refer to the 1281 Operators Manual. Use Table 15 to note the ratio indication on the 1281. Ignore the 0 value. Use the formula (742A actual value/ratio indication * 100 = actual 5520A value) and enter that ohm value into the 5520A actual value column.
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525A Performance Tests
Table 15. Ohms Ratio Table
5520A Actual Value ()
Range ()
742A Value ()
Ratio
525A Reading
90 Day Specification Specification
1 Year Specification
400 0 100 200 300 400 4000 0 1000 2000 3000 4000 0.02 0.06 0.1 0.14 0.18 0.03 0.065 0.10 0.135 0.17 0.03 0.07 0.11 0.15 0.19 0.002 0.006 0.01 0.014 0.018 0.003 0.0065 0.010 0.0135 0.017 0.003 0.007 0.011 0.015 0.019
First apply a four wire short to the 525A 4W RTD Ohm input. Set the 525A to the 400 range. Note the reading. Set the 525A to the 4000 range. Note the reading. Move the 525A 4W RTD Ohm input to the output of the 5520A. Output the same nominal values and note the 525A readings in the 525A reading column. Subtract the actual 5520A value from the 525A reading and ensure that it is within the specified tolerance.
525A
525A TEMPERATURE / PRESSURE CALIBRATOR
VOLTS
mA
100mA MAX
RTD
HI
OUTPUT
100V MAX
HI
STBY OPR VOLTS mA TC RTD TYPE UNITS
LO
20V PK MAX
LO
TC
INPUT/OUTPUT
OUTPUT
INPUT
ZERO
7
4W RTD
SETUP
8
CJC
9
C/ F
SHIFT
5520A 4
CE
Function
4
HI
INPUT SENSE
20V PK MAX
5
RECALL
6
AUTOSET
SET
1
RNG LOCK
2
LOCAL
3
EXP
LO
20V PK MAX
/
0
·
ENTER
ajr27f.eps
Figure 13. Connection for Measuring Ohms
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Testing Pressure Modules The Fluke 700 series pressure modules are calibrated separately from the 525A. The calibration follows the pressure module, so only a performance test is needed. Connect any of the Fluke 700 series pressure modules to the pressure module connector. Verify that the Calibrator reads pressure.
Calibration Adjustment
Adjusting the Calibrator requires no mechanical adjustment. All adjustments are performed electronically. The calibration is performed via serial communications port. The adjustments take place over the normal RS232 interface. Refer to Table 6 for a list of required equipment for performing the following procedures. Note that the adjustment for the Resistance Measure was designed to be especially flexible, allowing for the use of fixed resistors.
Initiating Communication Terminals can be set up using terminal communications software on a personal computer (PC). Connect a 9-pin null modem cable to the RS232 connector on the back of the Calibrator. Connect the other end of the cable to the PC/PC serial port. An adapter may be needed for terminals that use 25 pin D serial connectors. A terminal program such as Window HyperTerminal may be used in the PC.
The terminal settings need to be set as follows: Bits per second: 9600 Data bits: 8 Parity: None Stop bits: 1 Flow control: None Local echo: on
Starting Adjustment Mode The Calibrator needs to warm up for at least 30 minutes before performing these procedures. This will allow any thermal changes in the Calibrator to stabilize. If the unit has been repaired or is new, it should be given 24 hours to burn in. To initiate the calibration mode, use the PC to send the CAL_START command. The following will be displayed on the PC:
Calibration is password protected Enter Password:
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525A Calibration Adjustment
The password is 525. Enter the password through the PC keyboard and the following is displayed on the PC monitor:
Calibration Menu: 1: 100 mV Source 2: 1 V Source 3: 10 V Source 4: 100 V Source 5: 100 mA Source 6: Hi Ohms Source 7: Low Ohms Source 8: Hi Ohms Measure 9: Low Ohms Measure 10: SPRT 25 11: TC SOURCE 12: TC READ 13: TC CJC 14: Calibrate DAC Enter Selection:
Adjustment Sequence Manual calibration of the Calibrator is a menu driven process. The menu consists of 14 different menu selections for calibration of the different operating modes.
Certain functions must be calibrated before others. Table 16 lists the calibration dependencies and tells which functions are dependent on others being calibrated first. An X in a row indicates that the step in that column must be before the step in that row can be completed. These dependencies are only related to calibration adjustment. They are not intended to show the relationship between normal functionality and calibration.
Table 16. Calibration Dependencies 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A X X N/A X N/A X X X N/A 2 3 4 5 6 7 8 9 10 11 12 13 14 X X X X X
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14: Calibrate DAC, Digital to Analog Converter Adjustment If all of the functions that are affected by the digital to analog converter (DAC) adjustment are going to be adjusted, start with step 14 which adjusts the DAC. Do not adjust the DAC unless all of the ranges affected are going to be readjusted. During normal calibration adjustment, it is necessary to adjust the DAC. However, for example, if a mistake were made in the 100 V range, the user would not want to readjust the DAC. If it were readjusted, the user would have to readjust everything that depends on that range.
To adjust the calibration of the DAC from the menu, type 14 and then press the Enter key on the PC keyboard. No external connection is necessary. The DAC adjust will execute, save the calibration constants, then display the Calibration Menu on the PC.
1: 100 mV Source to 4: 100 V Source, Adjusting DC Source Adjusting the voltage output breaks down into four distinct ranges; each can be adjusted separately using menu selections 1-4. The adjustments are done in 2 parts. The first part sets the 0 and span values. The second part is to fine adjust the zero, span, and adjusts the linearity. The example below is for the 1 V range. The other ranges use the same steps with different voltage values. Refer to Table 17 for a list of equipment used in this section.
Table 17. List of Equipment for Voltage Calibration Adjustments Manufacturer Fluke Wavetek Model FLUKE-525A/LEADS 1281 Equipment Test Lead Set DMM
1. Connect the calibrator VOLTS HI and LO to the DMM input. 2. Set the DMM to DC Volts. 3. Type 2 and push the Enter key on the PC. The following is displayed on the PC:
First Calibration Point. Enter the Volts displayed:
4. When the reading on the DMM stabilizes, type the reading value on the PC and press Enter. After the value has been entered, the following is displayed on the PC:
Second Calibration Point. Enter the Volts displayed:
5. When the reading on the DMM stabilizes, type the reading value on the PC and press Enter. After the value has been entered, the following is displayed on the PC:
Second Calibration Point. Enter the Volts displayed: Adjust the 0 Percent of Scale, 8 for up 2 for down, Press Enter When Stable
The second part of the calibration adjustment follows. In the 10 key section of the PC keyboard, use the 8 (up arrow) to increase the output voltage displayed or 2 (down arrow) to decrease the output voltage displayed. Keep in mind the lag time between a change in output voltage to a stable display on the DMM. Make small changes then wait for a stable reading. Adjust the output so that you get a good, stable 0 V reading. When satisfied with the reading, press the Enter key.
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525A Calibration Adjustment
The PC display shows:
Please Wait... 25755 Adjust to 25 Percent of Scale, 8 for up 2 for down, Press Enter When Stable
The value is the raw A/D counts for this calibration point, followed by a prompt to adjust the 25 % of scale value. Use the 8 (up) and 2 (down) key on the PC to adjust the output to get a reading very close to 25 % of the range full scale. · · · · For the 100 mV range, 25 % is 25 mV For the 1 V range, 25 % is 250 mV For the 10 V range, 25 % is 2.5 V For the 100 V range, 25 % is 25 V
When satisfied with the reading, press Enter and the PC shows:
Please Wait... 2083980 Adjust to 50 Percent of Scale, 8 for up 2 for down, Press Enter When Stable
The value is the raw A/D counts for this calibration point followed by a prompt to adjust the 50 % of scale value. Use the 8 (up) and 2 (down) key on the PC to adjust the output to get a reading very close to 50 % of the range full scale. · · · · For the 100 mV range, 50 % is 50 mV For the 1 V range, 50 % is 500 mV For the 10 V range, 50 % is 5.0 V For the 100 V range, 50 % is 50 V
This process continues until the user goes through the 100 % range. Use the same procedures for those ranges. After the raw A/D counts are displayed, this calibration step is complete. The calibration constants for the range have been saved. Press Enter to return to the Calibration menu.
5: 100 mA Source, Adjusting DC Current Source Adjusting the DC current output is similar to the voltage source calibration adjustment. Just like the voltage calibration adjustment, this adjustment is executed in 2 parts. Part 1 sets the 0 and span values. Part 2 is to fine adjust the zero, span, and adjusts the linearity. Refer to Table 18 for a list of equipment used in this section.
Table 18. List of Equipment for Current Calibration Adjustments Manufacturer Fluke Fluke Wavetek Model FLUKE-525A/LEADS 742A-10 1281 Equipment Test Lead Set Resistance Standard, 10 DMM
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525A
Service Manual
The voltage is measured across a 10 shunt resistor instead of measuring current directly. Readings taken from the DMM need to be converted to mA (multiplied by 100) before they can be entered in at the PC. 1. Set the DMM to read DC Volts. 2. Use the test leads for the following connections: a. Connect the mA HI jack of the Calibrator to the high side of the current input of the 742A. b. Connect the mA LO jack of the calibrator to the low side of the current input of the 742A. c. Connect the high side of the sense output of the 742A to the high side of the voltage input of the DMM. d. Connect the low side of the sense output of the 742A to the low side of the voltage into the DMM. 3. Type 5 and then press the Enter key on the PC. The following will be displayed on the PC:
First Calibration Point. Enter the mAmps displayed:
4. When the reading on the DMM stabilizes, calculate the mA (multiply the voltage reading by 100) and type the mA on the PC then press the Enter key. After the value has been entered, the following shows on the PC:
Second Calibration Point. Enter the mAmps displayed:
5. When the reading on the DMM stabilizes, calculate the mA (multiply the voltage reading by 100) and type the mA on the PC then press the Enter key. After the value has been entered, the following shows on the PC:
Second Calibration Point. Enter the volts displayed Adjust the 0 Percent of Scale, 8 for up 2 for down, Press Enter When Stable
The second part of the calibration adjustment follows. In the 10 key section of the PC keyboard, use the 8 (up arrow) to increase the output voltage displayed or 2 (down arrow) to decrease the output voltage displayed. Keep in mind the lag time between a change in output voltage to a stable display on the DMM. Make small changes then wait for a stable reading. Adjust the output so that you get a good, stable 0 V reading. When satisfied with the reading, press the Enter key. The PC display shows:
Please Wait... 111260 Adjust to 25 Percent of Scale, 8 for up 2 for down, Press Enter When Stable
The value is the raw A/D counts for this calibration point, followed by a prompt to adjust the 25 % of scale value. Use the 8 (up) and 2 (down) key on the PC to adjust the output to get a reading very close to 25 % of the range full scale. · For the 100 mA range, 25 % is 250 mV When satisfied with the reading, press Enter and the PC shows:
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525A Calibration Adjustment
Please Wait... 2147203 Adjust to 50 Percent of Scale, 8 for up 2 for down, Press Enter When Stable
The value is the raw A/D counts for this calibration point followed by a prompt to adjust the 50 % of scale value. Use the 8 (up) and 2 (down) key on the PC to adjust the output to get a reading very close to 50 % of the range full scale. · For the 100 mA range, 50 % is 500 mV Repeat this process until the user goes through the 100 % range. Use the same procedures for those ranges. · · For the 100 mA range, 75 % is 750 mV For the 100 mA range, 100 % is 1 V
After the raw A/D counts are displayed, this calibration step is complete. The calibration constants for the range have been saved. Press Enter to return to the Calibration menu.
6: Hi Ohms Source, Adjusting High Resistance Source When calibrating the 5-4000 output range (High Ohms Source), the calibrator outputs two calibration points. After the output becomes stable, the values are entered at the PC.
1. Use the same test equipment listed in Table 16. 2. Make the following connections: a. Connect the HI RTD jack of the Calibrator to the high side of the Ohms measure sense jacks on the DMM. b. Connect the LO RTD jack of the Calibrator to the low side of the Ohms measure sense jacks on the DMM. c. Connect the HI RTD jack of the Calibrator to the high side of the Ohms measure current source jacks on the DMM. d. Connect the LO RTD jack of the Calibrator to the low side of the Ohms measure current source jacks on the DMM. It is important that the sense leads be on the bottom of the stack on the Calibrator Ohms source jacks. 3. Set the DMM to measure 4-wire ohms. 4. Type 6, then the Enter key on the PC. The PC will display:
First Calibration Point. Enter the Ohms displayed:
5. When the reading displayed on the DMM stabilizes, type the reading value on the PC and press the Enter key. After the value has been entered, the PC displays the following:
Second Calibration Point. Enter the Ohms displayed:
6. When the reading displayed on the DMM stabilizes, type the reading value on the PC and press the Enter key. After the second value has been entered, the Calibrator will return to the calibration menu.
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525A
Service Manual
7: Low Ohms, Adjusting Low Ohms Source When calibrating the 5-400 output range (High Ohms Source), the calibrator outputs two calibration points. After the output becomes stable, the values are entered at the PC.
1. Use the same test equipment listed in Table 16. 2. Use the same connections as in 6: Adjusting High Resistance Source. 3. Set the DMM to measure 4-wire ohms. 4. Type 7, then press the Enter key on the PC. The PC will display:
First Calibration Point. Enter the Ohms displayed:
5. When the reading displayed on the DMM stabilizes, type the reading value on the PC and press the Enter key. After the value has been entered, the PC displays the following:
Second Calibration Point. Enter the Ohms displayed:
6. When the reading displayed on the DMM stabilizes, type the reading value on the PC and press the Enter key. After the second value has been entered, the Calibrator will return to the calibration menu.
8: Hi Ohms, Adjusting High Resistance Measure When adjusting the calibration for the 5-4000 Ohms Measure range (High Ohms Measure), the Calibrator will first measure a short and then two resistances. Refer to Table 19 for a list of equipment used in this section.
Table 19. List of Equipment for High Ohms Measure Calibration Adjustments Manufacturer Fluke Fluke Fluke Wavetek Model FLUKE-525A/LEADS 742A-10K 5520A 1281 Equipment Test Lead Set Resistance Standard, 10K Calibrator DMM
1. Insert a 4-wire short into the 525A 4W RTD jacks. 2. Type 8 then press the Enter key on the PC. The following will show on the PC:
Input 0 Ohms, Press Enter When Stable
3. Allow a few seconds for stabilization, then press the Enter key. In a few moments the following appears on the PC:
Input ~2000 Ohms, Enter the actual value when stable:
The ~2000 indicates that the desired resistance is about 2000 . The actual resistance is not as important as the accuracy with which the value is known. The method described below uses the 1281 to establish a ratio between the 552