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460 Handheld 20MHz Digital Oscilloscope User's Guide
The Value Leader
TM
www.tpi-thevalueleader.com
Test Products International, Inc. 9615 SW Allen Blvd. Portland, OR 97005 Ph: 503-520-9197 ! Fax: 503-520-1225 E-mail: [email protected]
460 User's Guide
Copyright © 2001 Test Products International, Inc. All Rights Reserved 08/01
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460 User's Guide
Table of Contents
C1 - Introduction........................................................................................C1-1 Features ..........................................................................................C1-2 Specifications ..................................................................................C1-3 Scope Modes ........................................................................C1-3 Multimeter Modes ................................................................C1-5 C2 - Getting Started ..................................................................................C2-1 Equipment Needed ..........................................................................C2-1 460 Setup ........................................................................................C2-1 Measuring Voltage ..........................................................................C2-3 Measuring Frequency ......................................................................C2-3 Measuring Resistance......................................................................C2-4 Testing Continuity ............................................................................C2-4 Diode Test ........................................................................................C2-4 C3 - Operation............................................................................................C3-1 Principal Connectors and Keys ........................................................C3-1 Key / Screen Menus ........................................................................C3-3 C4 - Advanced Functions ..........................................................................C4-1 Triggering ........................................................................................C4-1 Trend Mode......................................................................................C4-1 Glitch Capture ..................................................................................C4-2 Saving Screens ................................................................................C4-2 Using the 10:1 Probe ......................................................................C4-3 10:1 Probe Compensation Adjustment ............................................C4-3 C5 - Using Adapters ..................................................................................C5-1 Temperature Adapter - A301............................................................C5-1 High Current Adapter - A251 / A256 / A296 ....................................C5-1 Low Current Adapter - A254 ............................................................C5-2
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460 User's Guide
Current Shunt Adapter - A130 ........................................................C5-2 Pressure Adapter - A620 ................................................................C5-2 PC Software & RS232 Cable - A404 ................................................C5-3 C6 - Safety Considerations ........................................................................C6-1 Instrument ......................................................................................C6-1 Environmental..................................................................................C6-2 Appendix A - Test and Calibration ................................................................A-1 Appendix B - Maintenance Considerations ..................................................B-1 Appendix C - Glossary ................................................................................C-1 Appendix D - Optional RS-232C / PC Interface............................................D-1 Appendix E - Troubleshooting ......................................................................E-1
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460 User's Guide
Introduction
Chapter 1 Introduction
This manual describes the TPI Scope Plus 460 and its functions. Normal and advanced functions are covered in detail, as well as interactions with computers and other instrumentation. A full chapter is also devoted to safety considerations, both instrument based and interactively. The following is a brief chapter and appendix summary: Chapter 1 Chapter 2 Covers the introduction, features and Specifications. Getting Started gets the new user up and running in the shortest time possible. The basic functions are introduced in a hands on style designed to familiarize the user with the keypad and screen display. Explains all the normal functions of the TPI Scope Plus 460, including buttons, menus, screen displays, and a sequencing guide for both external key actions and their interaction with software driven menus. Explains more advanced functions such as triggering, glitch capture, trend mode, and saving screens. Explains and illustrates uses of probes and adapters including pressure, temperature, and current shunt adapters. This chapter also introduces general aspects of the optional optically isolated RS-232 interface. This important chapter details operating methods and tips designed to preserve both the life of your instrument, and safety factors to prevent human injury. The text is divided into Instrument and environmental safety subsections.
Chapter 3 -
Chapter 4 -
Chapter 5 -
Chapter 6 -
Appendix A - This appendix covers what to look for, and how to make simple tests to find out if your TPI Scope Plus 460 requires replacement parts or calibration. Appendix B - This Maintenance appendix gives tips on how to keep your TPI Scope Plus 460 in top operating condition by assuring constant peak performance. The appendix also covers battery servicing and replacement. Appendix C - A glossary describing the meanings of terms associated with the 460 and its working environment. Appendix D - This appendix introduces and explains the powerful RS-232C Interface option. All aspects are covered from Installation to C1-1
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Introduction
Special Applications. Appendix E - This Troubleshooting appendix covers problems that may arise during installation or operation of your new TPI Scope Plus 460.
Features
The following features exist for the TPI Scope Plus 460: " 20 MHz Bandwidth Enough bandwidth to capture signals from AC/DC drive motors, sensors, actuators, line and control voltages, UPS and industrial machines. Sample Rate A real time sampling of 25 megasamples/sec to capture spikes and dropouts of industrial signals. Dual Input View two waveforms on the display for comparison and troubleshooting. True RMS DMM Includes a 4000 count True RMS DMM that measures AC/DC volts to 600V, frequency to 20MHz, resistance to 20M Ohm, diode test and continuity audible tone. Autoranging Autoranging capability across Voltage, Timebase and Frequency. Bright LCD Backlight Easy-to-see display in any light condition with user-adjustable backlight brightness levels Optically Isolated RS232 Output Transfer data safely without any direct connections to your computer's systems security. Optional Accessories Temperature Adapter to measure temperature from -40 to 500oF (A301). Pressure Adapter to measure pressure from -30 to 500psi (A620). Protective Boot (A405). Soft Carrying Case with Shoulder Strap (A905). RS232 cable and software (A404). Current Adapters: o A254 - For measuring low current in milliamps o A256 - Up to 400 AC/DC amps
"
" "
" "
"
"
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Introduction
o
A296 - Up to 1000 AC/DC amps
Specifications
Display: Size Pixels LCD type Back Light Memory: Waveform Setup Power: External Internal Battery Battery Operating Time Charging Time 76mm X 76mm (3" X 3") 240 X 240 pixels STN Normally Gray or Black CCFL
Screens (2) User setup (1)
Power Adapter (5.5V / 2A) Ni-MH 1.2V X 4 More than 2.5 hours with bright backlight 10 hours
SCOPE MODES Horizontal: Samples per division Time/division Modes Accuracy
25 samples / div. Equivalent sampling 50ns to 500ns/div Real time sampling 1us to 2s/div Single, Normal, Auto, Glitch Real time sampling +/- (0.1% + 0.04 time/div) Equivalent sampling +/- (0.5% + 0.08 time/div)
Vertical: Sampling Rate Bandwidth
Resolution Channel Coupling Input impedance Sensitivity
25 Mega samples per second DC Coupled 1:1 shielded test leads ; DC to 10MHz 10:1 probe ; DC to 20MHz AC Coupled 1:1 shielded test leads ; 10Hz to 10MHz 10:1 probe ; 10Hz to 20MHz 8 bits 2 AC,DC,GND Approx. 1M Ohm 50mV to 200V/div 1,2,5 sequence
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Introduction
Accuracy Display modes Maximum Input Voltage Trigger: Position Mode Source Slope Sensitivity
+/- (3% + 0.05 range/div) CH1, Dual 600V
Ver 1; Fixed Position / Ver 3; Adjustable Position Free run, normal Internal (CH1/CH2) Positive/Negative Real time sampling .... 2 divisions or more Equivalent sampling .... 3 divisions or more
Trend Plot: Plot Time Plot Data Type
30sec/div to 1-hour/div Max / Min Selectable
Temperature Measurement: Optional Adapter A301 (k - Type thermocouple) Range -40 F to 500 F Accuracy +/- (1.5% + 5 digits)
Pressure / Vacuum Measurement: Optional Adapter A620 Range Pressure 500 psi Vacuum 30 inHg Accuracy Pressure +/- (5% + 5 digits) Vacuum +/- (1.5% + 5 digits)
Current Measurement: Optional Adapter 1 Range Accuracy ( 0 - 40A ) (40 - 400A) Optional Adapter 2 Range Accuracy ( 0 - 40A ) (40 - 400A) Optional Adapter 3
A251 (AC AMPS) 0 - 40A / 40 - 400A +/- (2.0% + 10 digits , 50 / 60 Hz) +/- (2.0% + 10 digits , 50 / 60 Hz) A256 (AC/DC AMPS) 0 - 40A / 40 - 400A +/- (2.0% + 10 digits , 50 / 60 Hz) +/- (2.0% + 10 digits , 50 / 60 Hz) A296 (AC/DC AMPS)
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Introduction
Range Accuracy ( 0 - 400A ) (400 - 1000A)
0 - 400A / 400 - 1000A +/- (2.0% + 10 digits , 50 / 60 Hz) +/- (2.0% + 10 digits , 50 / 60 Hz)
MULTIMETER MODES DC Volts (CH1/CH2) Range Resolution 400mV 0.1mV 4V 0.001V 40V 0.01V 400V 0.1V 600V 1V
Accuracy +/- (0.5% + 5 digits) +/- (0.5% + 5 digits) +/- (0.5% + 5 digits) +/- (0.5% + 5 digits) +/- (0.5% + 5 digits)
AC Volts (CH1/CH2) Range Resolution 400mV 0.1mV 4V 0.001V 40V 0.01V 400V 0.1V 600V 1V
Accuracy 20Hz to 50Hz; +/- (2% + 20 digits) 50Hz to 1kHz; +/- (1% + 10 digits) 1kHz to 20kHz; +/- ( 2% + 10 digits) 40Hz to 400Hz; +/- (1% + 10 digits) 40Hz to 400Hz; +/- (1% + 10 digits)
Frequency (CH1/CH2) Range Resolution 100Hz 0.01Hz 1KHz 0.1Hz 10KHz 1Hz 100KHz 10Hz 1MHz 100Hz 10MHz 1kHz 20MHz 10kHz
Accuracy +/- (1.0% + 10 digits) +/- (0.5% + 5 digits) +/- (0.5% + 5 digits) +/- (0.5% + 5 digits) +/- (0.5% + 5 digits) +/- (0.5% + 5 digits) +/- (2.5% + 5 digits)
OHM (CH1 ONLY) Range Resolution 400 Ohm 0.1 Ohm 4k Ohm 1 Ohm 40k Ohm 10 Ohm 400k Ohm 100 Ohm 4M Ohm 1k Ohm 20M Ohm 10k Ohm
Accuracy +/- (0.75% + 5 digits) +/- (0.5% + 5 digits) +/- (0.5% + 5 digits) +/- (0.5% + 5 digits) +/- (1.0% + 10 digits) +/- (3.0% + 20 digits)
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Introduction
Continuity (CH1 ONLY) Range Resolution 4 K ohm 1 ohm
Accuracy Beeps < 0.1 K ohm , +/- (2% + 5 digits)
Diode (CH1 ONLY) Range Resolution 4V 1 mV
Accuracy Open circuit voltage < 5 V Short circuit current < 5 mA Reading accuracy; +/- (2% + 5 digits)
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Getting Started
Chapter 2 Getting Started
This chapter will get you started with the TPI Scope Plus 460. It will include initial power up, followed by a series of DMM and static tests. More detailed operations will be the subject of the next chapter. Refer also to the chapters and appendices covering specifications and maintenance if you run into problems outside the scope of this chapter. Also feel free to check with service support using the phone numbers given at the beginning of this manual.
Equipment Needed
Required: " Fully operational TPI Scope Plus 460 with batteries fully charged " Set of probes with alligator clip attachments available " Set of fixed or variable resistances. " Set of fixed or variable inductances. " Set of fixed or variable capacitances. " Static or variable DC voltage source. Optional: " Signal generator source with varied outputs " Random glitch or voltage spike generator
460 Setup
1. 2. Use the tilt stand if necessary to set up the instrument in a readable position. Switch the unit on by pressing POWER ON button for 3 seconds. If the unit will power on, attach the power adapter. Initial charge of the battery must be made with 460 turned on. If the Power adapter is attached, check the battery level by pulling out the adapter and checking if there is any change to the brightness of the display (For optimal performance, the battery should be fully charged even with the Power adapter attached). Check the Contrast. Refer to Figure 2-1, and press the USER button. Note the Contrast menu button is displayed on the screen above F2. - Press F2 and note the menu item on the screen is now darkened. Press the Up arrow to increase the contrast and the Down arrow to reduce the contrast. Check the Brightness (-there are ten levels). Refer to Figure 2-1, and press the Brightness button (Sun Icon) to decrease the brightness. To increase the brightness, continue pressing the brightness button until you have reached the bottom level, at which C2-1
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460 User's Guide
Getting Started
3. Press F2 (below the Contrast Label).
4. Press the Up or Down direction arrows to change contrast.
2. Press the User Button
1. Press the POWER ON Button
Figure 2-1. Contrast Adjustment with Low Visibility
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Getting Started
time it will revert to the maximum brightness level.
NOTE: The Brightness control effects the backlighting whereas Contrast effects the intensity of the liquid crystal display (both for the tracing beams and the text display).
6. You have now completed the basic setup. Press Ch A (Channel A), to exit the user setup mode and ready the instrument for Multimeter operations.
Measuring Voltage
1. With the 460 set for Input A (Ch A button), use the down arrow to set the highlight on DCV. Press Enter. Press the green V key, and connect the probes to a DC Voltage source. The voltage will appear in alphanumeric text at the top left of the screen. The trace line A should be steady, but if there are any AC components present on the line it will also show these (especially in the case of partially rectified AC).
2.
NOTE: Pressing the Green key V selection first will ensure you are not being limited by the millivolt range. If the voltage reading is then read as a small value, use the mV side of the green rocker key to display the millivolt range on the screen.
3. Disconnect the DC Voltage source and press Ch A (Channel A blue button). Use the Up arrow to move the screen highlight to ACV. Press Enter. Press the green V key, and connect the probes to the AC source. The voltage can be read at the top left of the screen expressed as an RMS value. The trace line A will show the shape of the AC voltage source.
4.
Measuring Frequency
1. With the 460 set for Input A (Ch A button), use the down arrow to set the highlight on Freq. Press Enter. Connect the probes to a frequency source. The frequency will be shown in alphanumeric text at the top left of the screen. The trace line A will show the nature of the frequency source.
2.
Notes on Trace Stability: a). Ensuring that the Channel B trace is off when making frequency measurements on the A channel, will reduce clutter on the screen, and make the A trace easier to read.
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Getting Started
b). Using the HOLD/RUN button will freeze the trace and allow waveform characteristics to be measured precisely against the background grid.
Measuring Resistance
1. With the 460 set for Input A (Ch A button), use the down arrow to set the highlight on OHM. Press Enter. Connect the probes across the resistance source. The resistance value is shown in two forms. First as alphanumeric text at the top of the screen. Secondly, the value is shown visually against a calibrated bar. The value of the bar is shown at the base of the screen. For instance, if a resistance of 12.00 K Ohms is being read, a bar of value 40K Ohms will typically be displayed, and the actual value of the resistance will show as 12.00 against that bar
2.
Testing Continuity
1. With the 460 set for Input A (Ch A button), use the down arrow to set the highlight on Beep. Press Enter. Connect the probes across the source to be tested. If the line is closed (equiv. of short circuit) or not offering more than 100 Ohms of resistance, the full beep will be heard, and the bar will show the degree of resistance (if any).
2.
Note: The continuity test function can also be used to test the resistance in a path up to a value of 4K Ohms. The actual value will be shown alphanumerically in the top left of the screen, and also shown graphically against a bar having a span of 0 to 4K Ohms
Diode Test
1. With the 460 set for Input A (Ch A button), use the down arrow to set the highlight on DIODE. Press Enter. Connect the probes across the diode in the +/+ direction. A total resistance should be noted (The full bar shows no reverse current flow). Connect the probes to the diode in the normal +/- direction. The bar display should show an open or almost open condition. - Forward bias is shown against a scale of 2.0 volts and is also displayed alpha-numerically at top left of the screen.
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Operation
Chapter 3 Operation
This chapter provides a general overview of the tpi Scope Plus 460 from an operations point of view. The keys and adapter connectors will first be identified followed by a pictorial description of the key and screen menu functions.
Principal Connectors and keys
Figure 3-1 shows the general layout of the front panel and side connectors. Many of the functions are straight forward and identified in the illustration. The numbered items in the diagram need additional explanation and are detailed below: 1. Ch A This key controls the display of oscilloscope Channel A. The first screen requires the user to first identify the nature of the display, e.g., AC Volts, DC Volts, Frequency, etc. Then, after pressing ENTER, the Channel A trace is displayed as well as the correct alphanumerics. Ch B This key controls the display of oscilloscope Channel B. The first screen requires the user to first identify the nature of the display, This list is different from Channel A and includes specialized measuring scales such as oC, oF and Psi, etc. After selecting the scale, press ENTER , and the Channel B trace is displayed. S TIME nS This rocker switch controls the oscilloscope timebase. Pressing the left side decreases the sweep rate in 1, 2, 5, increments down to 2-seconds per division. Pressing the right side speeds the sweep rate in increments up to 50-nano seconds per division. Sweep Rate is displayed above the TRIGGER label at the base of the screen mV / V This vertically orientated rocker switch controls the vertical sensitivity for the A Channel oscilloscope. The scale is in 1, 2, 5, increments from 50mV to 200V per vertical division. The readout is at the extreme left of the display just above the A MOVE label. mV / V This rocker switch is identical to Callout #4 except applicable to Channel B. The readout is at the extreme right of the display just above the B MOVE label. This is the brightness button. It controls the screen background intensity of the
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5
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Operation
backlit LCD screen. The button has ten cycles of brightness, after which it resets to the first position.
Common (Ground) Channel A Connector
Channel B Connector
Ch A
Alphanumeric Display Area
COM
Ch B
RS-232C Connector
Dual Trace Display Area Power Plug Menu Area
Menu Function Keys (F1-F4)
2 F1 F2 F3 F4 Ch B
Highlight Direction Arrows
1
Ch A
S TIME nS
3 4
Function Acknowledge Key
mV
ENTER
mV V
5 6
V
AUTO SCOPE USER
HOLD RUN
460 Power Switch
SAVE
POWER ON
7 9 8 10
11
Figure 3-1. 460 Front Panel layout C3-2
460 User's Guide
Operation
7.
AUTO This is the Auto Ranging and optimal setting button. In the AUTO mode, the 460 will sense the parameter being measured and automatically adjust the oscilloscope timebase to suit. The button also toggles between AUTO and MANUAL modes. Note that the previous manual settings are lost once auto mode has activated. SCOPE This is a dual function oscilloscope switch. Initial activation (Scope /S1) sets the oscilloscope program to display the SCOPE INPUTS interactive menu. Activating the SCOPE switch a second time, sets the program to display the Channel A waveform, the Channel B waveform (if it is switched ON), and the A / B MOVE, TRIGGER / TREND selection menu. Pressing the switch a third time will toggle the program back to SCOPE INPUTS. HOLD / RUN This is a toggle switch that allows the user to freeze the currently dis played waveforms. Once frozen, the user can choose to record the waveform using the SAVE key (see callout #11), or to press the HOLD / RUN key a second time to unfreeze the display. USER This is a toggle switch that allows a user to interrupt most ongoing programs to revert to a setup mode to adjust Contrast, RS-232C output, or Power Down, and then revert to the original program by pressing the button a second time. Note that the POWER DOWN menu selection allows an automatic timed power down for special functions. SAVE This is a toggle switch that allows a screen save (traces only) for a maximum of two saves and/or recalls. You can delete an existing capture, or automatically overwrite to the selected memory. Pressing the button a second time reverts to the original display.
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Key / Screen Menus
The following tables provide a graphical explanation of the key and menu interactions and menu item sequencing. Most sequences begin with a key and are at the left of the diagrams. The colors of the keys are below the appropriate boxes. Note that the two Scope entries (Scope / S1 in Table 3-1, and Scope / S2 in Table 3-2) represent the two sequential functions of the same switch.
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Table 3-1. 460 User Function / Menu Interactions Part 1 CHA Blue CHB Blue ACV DCV FREQ
1mV /oC 1mV /oF 1mV /Psi 1mV /inHg
ACV
DCV
FREQ
OHM
BEEP
DIODE
OFF
ON
ACA
1mV/A
10mV/A
100mV /A 100mV /A DCV GND
DCA
1mV/A
10mV/A
SCOPE / S1 Brown
A
ACV
MODE
AUTO
NORM
SINGLE
GLITCH
B
ACV
DCV
GND
OFF
F1
PROBES SELECT
SEL A
1:1
10:1
SEL B F2 Probe Adjust Enter
1:1
10:1
F4
SAVE Brown
SAVE
RECALL
DELETE
SCREEN 1
SCREEN 2
NO
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Operation
Table 3-2. 460 User Function / Menu Interactions Part 2 USER Brown
EXIT CONTRAST RS232C POWER DOWN
AFTER 10 MIN AFTER 20 MIN AFTER 30 MIN
F1
F2
F3
F4
SCOPE / S2 Brown
F1
A MOVE TRIGGER F1
DISABLE EXIT
F2
F2
SOURCE A, B
F3
TRIG. LEVEL TRIG. SLOPE
F4
F3
TREND
F1
EXIT
F2
MAX
F3
MIN
F4
B MOVE
F4
RESTART
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Advanced Functions
Chapter 4 Advanced Functions
This chapter assumes the user has now become proficient with the general use of the tpi Scope Plus 460, and is ready to utilize the more enhanced operations of the 460's built-in oscilloscopes and related logic circuits. In this chapter we will look at triggering, trend mode and different aspects of capturing glitches. We will also look at screen saves, use of the 10:1 probe and probe adjustments.
Triggering
Trigger level refers to the control of the threshold voltage amplitude level that is triggered from the input signal, in turn synchronizing the waveform. Once the voltage exceeds or recedes the trigger level, the meter will draw a trace of the signal with greater stability allowing the technician to analyze the portion of interest more efficiently. With Channel A on the 460 active, connect the Common and Probe Lead A to a signal source (Sine Wave preferred), and proceed with the following steps: 1. 2. 3. 4. 5. Click SCOPE, then select A=ACU, Mode=Auto, B=Off. Then select ENTER Move the highlight to TRIGGER and press ENTER Use the mV / V Channel A rocker key to size the waveform. With the highlight on TRIG. LEVEL, use the up and down keys to stabilize the waveform. Observe that you have now stabilized the waveform without changing the frequency and without intentionally freezing the waveform. So this is a stabilized live waveform suitable for analysis or monitoring. Use the SOURCE or TRIG. SLOPE highlight options in conjunction with the direction buttons to modify the waveform. Use the EXIT box (F1) to Exit from the trigger operation and / or to move the waveform position on the screen.
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7.
Trend Mode
The Trend mode graphs signals over time to capture problems. This option has menu boxes but is inactive on the current model of the 460. C4-1
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Advanced Functions
Glitch Capture
The tpi Scope Plus 460 incorporates this feature for capturing intermittent or single event voltage spikes occurring in a circuit. The spike is automatically detected, captured, and displayed for analysis on the screen. To perform this task as a test, you will need a signal generator with a spike or glitch generating capability, or a means of imposing a glitch onto an otherwise stable signal. With Channel A on the 460 active, connect the Common and Probe Lead A to a signal source (Sine Wave preferred), and proceed with the following steps: 1. 2. Click SCOPE, then select A=DCU, Mode=Glitch, B=Off. Then select ENTER Use the up and down keys to center, or lower the waveform (-the spike will usually be positive in test cases). Then introduce the spike (-this is usually a button on many test signal generators). If the 460 is performing correctly, you should now have the glitch on your screen, complete with leading and trailing edges so that rise time as well as other parameters can be measured. Exit the glitch condition by selecting SCOPE, then change MODE = NORM, then press ENTER.
3.
4.
Saving Screens
You can save any screen capture from Channel A, Channel B, or two instances of both channels simultaneously. They can be recalled to the screen, or made available to your computer if you also have the RS232 software option. As an example of simultaneous capture, connect the Common and Probe Lead Ch A to one signal source, then the Probe lead Ch B to a different signal source, and proceed with the following steps: 1. 2. Click SCOPE, then select A=ACU, Mode=Glitch, B=ACU. Then select ENTER Use the up and down keys in conjunction with the A & B Move boxes at the base of the screen to position both waveforms Press the SAVE key, select SCREEN 1, and then select ENTER
3.
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NOTE: There may be no change to the screen after the last operation. This is normal.
4. Press SAVE again, then select the menu item RECALL, then SCREEN 1, then ENTER.
5.
You should now see your saved waveforms with the label RECALLED SCREEN 1, immediately below the waveforms.
NOTE: The next screen save using the same screen number (e.g. Screen 1), will overwrite the previous (Screen 1) save.
6. Select the on-screen EXIT to leave the Save program, then press SCOPE to reset the scope parameters
Using the 10:1 Probe
The TPI Scope Plus 460 is also available with selectable attenuation probes (e.g. P/N SP60B). These are usually in the form of a probe body with a 3-position switch, 1-meter co-axial lead terminating at the meter end with a BNC connector with an adapter for the 460 socket. This set-up contains its own ground lead exiting from the probe body, and is supplied with a number of different probe tips. Attenuation selection is X1, X10, and a ground reference position. Use of the 10:1 probe extends the bandwidth to 100 MHz when used in the X10 position. To use the 10:1 probe with the 460, press the SCOPE button, then the F1 key when the SCOPE INPUTS / PROBES SELECT menu boxes are present on the screen. With the 10:1 Adapter in the CH A socket, use the Up / Down keys to highlight 10:1 on the SEL A side of the displayed Probe Selection menu box. Then select ENTER When using the 10:1 probe on different dual oscilloscope channels, or from instrument to instrument, always perform the adjustment procedure which follows.
CAUTION: Do not use the 10:1 probe for resistance measurements.
10:1 Probe Compensation Adjustment
The following adjustment procedure will ensure that the displayed waveforms will be matched to the correct division on the display. There are two methods to compensate the 10:1 Probe. The first and recommended way is to
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Advanced Functions
connect the probe to the 460 and set up a 1 KHz square wave using an external signal generator.
Method 1
1. 2. Connect the 10:1 Adapter BNC connector to the Ch A socket on the 460. Press the 460 SCOPE key. Then, when the SCOPE INPUTS display is present, press the F2 key below the PROBE ADJUST selection box. Attach the 10:1 Probe tip to the signal generator, and use the ground wire from the probe body to connect with the signal generator ground. With a square wave displayed on the 460 screen, adjust the trimmer located in the BNC plug to maximize the squareness on the top and bottom of the square wave. On the 460, press the F4 key, or the ENTER key to exit the program.
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Method 2
1. Connect the 10:1 Probe BNC adapter to the Ch B input at the top of the 460. Then attach the 10:1 Probe Tip with the Banana Adapter to the Ch A input. Press the SCOPE key. Then, when the SCOPE INPUTS display is present, press the F2 key below the PROBE ADJUST selection box. Following the instructions on the screen, use the screwdriver, supplied with the 10:1 Probe kit to adjust the trimmer in the BNC plug. Adjust the trimmer to obtain fully squared edges on the displayed square wave. On the 460, press the F4 key, or the ENTER key to exit the program.
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Using Adapters
Chapter 5 Using Adapters
This chapter covers general information on the accessories available for use with the tpi 460 Handheld Oscilloscope. For detailed information, please refer to the data sheets provided with each adapter.
Temperature Adapter - A301
This adapter is used in conjunction with K-type probes to measure a variety of temperature targets with ranges from -40 to 500oF. tpi offers almost 20 different types of thermocouple probes that work accurately with the A301. The A301 (regardless of the type of thermocouple use, has a standard output of 1mV DC per degree Fahrenheit. The range of the A130 is -40 to 500oF, therefore the output range is 960mV to O.5V. On the 460 this equates to using the standard DCV scale on Channel A, or the 1mV/oF scale on the B Channel (Press Ch B, make selection, and press F4 to Enter).
NOTE: The A Channel is recommended for this adapter, as the Ch A plug orientation on the 460 allows the Adapter On/Off switch to face the user.
The A301 comes with a 9V battery and a standard 2-Pin plug that sockets directly into the top of the tpi Scope Plus 460.
High Current Adapters - A251 / A256 / A296
o A251 - A clamp-on adapter that measures up to 400 AC amps. o A256 - A clamp-on adapter that measures up to 400 AC and DC amps. o A296 - A clamp-on adapter that measures up to 1000 AC and DC amps. All three adapters have some common operating parameters. They should only ever be used on a single wire. Clamping onto bundles or any more that one wire will result in erroneous readings. Set up the 460 before making the test and ensure that power is initially off to the circuit under test and that the input cable is inserted using the correct polarities. On the 460, use ACV for making AC measurements, and DCV for making DC measurements. In addition, use the V rocker button on he instrument to initially go to the highest voltage rating when making an initial measurement (200V on both scales). All the High Current measurement adapters use a 9V battery (supplied). If the battery runs low,
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Using Adapters
the red LED will come on and remain on until it is exhausted or the battery is replaced.
Low Current Adapter - A254
This small clamp-on adapter measures currents one amp and below accompanied by voltages up to 1000V in either AC or DC. Plug the unit into the upper sockets of the 460. Use DCV on Channel A (Ch A) and convert 10mV to 1.0 amp with the 254 set to 10mV/A and 100mV to 1.0amp with the 254 set to 100mV/A, or Channel B (Ch B) and use either the 10mV/A DCA or 100mV/A selections (depending on the appropriate A254 setting) to read both millivolts and equivalent amps at the top of the screen. Be sure to plug the A254 into the correct sockets of the 460 for the channel being used.
CAUTION: This adapter is designed to measure currents up to 1 Amp. Attempts to measure currents greater than 60 Amps could damage both the adapter and the 460 measuring instrument.
The A254 uses a 9V battery (supplied), and includes a detachable instrument head socket (2-pin to co-axial), and a zero adjust control.
Current Shunt Adapter - A130
This adapter is an inexpensive way of extending the current range of your tpi 460 Handheld Oscilloscope to 30 amps. The A130 comes with two probes and is used in series with the circuit to be measured. The unit uses the power being measured and requires no batteries. Plug the unit into the upper sockets of the 460. Use DCV on Channel A (Ch A) and convert 0.1mV to 0.1 amp, or Channel B (Ch B) and use the 1mV selection to read both millivolts and equivalent amps at the top of the screen. Be sure to plug the A130 into the correct sockets of the 460 for the channel being used.
NOTE: Channel A is recommended for the A130 adapter, as the Ch A plug orientation on the 460 allows the Adapter On/Off switch to face the user.
Pressure Adapter - A620
This adapter can measure air densities from a vacuum of 30 inHg to a pressure of 500 psi. Connect the adapter to the upper sockets of the 460. Use DCV on Channel A (Ch A) and convert 0.1mV to 1 psi for pressure and 1 inHg for vacuum, or Channel B (Ch B) using the 1mV/PSI or C5-2
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Using Adapters
1mV/inHg selections as required. On the A620, use the BAR switch position to measure vacuum or the X10psi position to measure pressures from 1 to 500psi. Use the ZERO control only if you know the pressure to be zero and stable, or at a standardized pressure.
The A620 uses a 9V battery (supplied) and includes a 1/4 inch NPT pressure port connection at the end of a 2-Meter flexible cable.
PC Software and RS232 Cable - A404
This software allows the 460 to download data and waveforms to any computer environment running Microsoft Windows. The RS232 interface utilizes a fiber optic connection to shield the data from electro magnetic radiation sources, and therefor from potential signal degradation. Using the A404 package you can download data and put the information into spreadsheets and charts for incorporating into reports and other documents. Reports from different units can also be merged to produce one report. In addition, graphs can be shown with the identification number of the instrument used, enabling data to be cross-checked against calibration records helping to ensure full traceability. Since live waveforms can also be transmitted to the computer via the RS232 connection, you can compare stored waveforms to current waveforms for some types of fault recognition. Refer to Appendix D for RS232 interactions with your personal computer.
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Safety Considerations
Chapter 6 Safety Considerations
This chapter deals with various aspects of safety, both for personnel and the instrument. Also included is a List of safety signals and their meanings.
Instrument Cautions
o Test the Instrument before using o Check Backlighting and Contrast (this will also accomplish a quick test on the battery level). o Check both oscilloscope channels. - A simple standard waveform test will usually accomplish this. Check the Test Leads and/or Adapter o If there is a break or intermittent in the test leads, it will have the same effect as a malfunctioning instrument. o Check the adapter using a known sample or set-up before using on the device or environment under test. o Test Connections o Check the security and quality of both the adapter connections to the instrument and DUT (Device Under Test) connector points. Disconnect Power to the Circuit (Unless using Clamp-On's) o This step provides two safety factors. The first ensures that the operators hands are not in the vicinity of dangerous voltages. The second allows you to check that the instrument is set up to read the right values before power is present at the DUT. o Understand the circuit being measured o Failure to understand the circuit to be tested has the same level of risk as not setting up the instrument before power is applied to the circuit. Namely the risk of too much power for the level of measurement. Keep the Instrument Non-Parallel to the Circuit o If the instrument, or any substantial length of test cable is parallel to and/or in close proximity to the bulk of the DUT or high current carrying cable, the test cable will pick up some of the radiation and be affected by it. This is important when making precise measurements or when seeking a stable waveform.
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Safety Considerations
Personnel/Environmental Factors / Warnings
Assign a Checker o Arrange to have someone check on you periodically. This is especially true of high voltage environments. An unconscious worker stands a better chance of survival if resuscitation is given in the shortest time after an accident. Do not attempt to measure unknown voltages or currents o With modern cabling, it is easy to assume that a small size wire or cable is carrying a voltage or current that is less than actual. Either assumption can have disastrous effects for both operator and instrument. Do not touch any exposed part of the test lead assembly o Some types of test leads have close to exposed metal parts that could potentially come into contact with the body, especially hands or lead pencils and other conducting items.
List of Danger/Warning Signals
The following are International Danger/Warning signals with an abbreviated explanation of their meanings. This label signifies that there is a distinct level of danger in this area. This sign is usually accompanied with symbols denoting the exact type of danger present.
This combination label signifies that a significant level of danger exists in this area that can effect the eyes. This symbol denotes that shaded goggles should be worn.
This combination label signifies that there is a distinct possibility of a fire hazard in this area (--an explosion symbol is sometimes substituted for the fire symbol in similar situations). Do not carry combustible materials in this area
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This combination label signifies that there is a strong possibility of electrical shock in this area. Proper attire, and especially insulated footwear are required in these areas.
This International symbol signifies that conditions exist that could result in bodily harm. The symbol usually occurs in conjunction with a symbolic description of the type of hazard that exists.
This symbol indicates that there are open gears in the area which could snag clothing and risk injury to the wearer. Avoid wearing loose clothing and beware of test instrumentation with long leads attached.
This symbol indicates that a hazard exists in this area which could effect exposed skin areas. The nature of this hazard could be chemical of temperature based. Wear gloves at all times and be careful of any other skin contact.
This International symbol indicates that a danger exists which could damage equipment that you carry into the area. Identify proper grounding and use in conjunction with test equipment at all times
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Test and Calibration
Appendix A Test and Calibration
This chapter is designed to re-affirm that your TPI Scope Plus 460 is functioning correctly and is on a par with the original calibration. This test and calibration procedure can be used as an annual test, goods inward (Acceptance) test, or re-affirmation test when readings have not been expected ones.
Test Procedures
The TPI Scope Plus 460 has no built-in test programs, however, the following procedures can be used to perform a quick functional check on most 460 operations. Procedural titles that are followed by an asterisk (*) are less important, and can be considered optional in cases where a quicker spot test is required.
Initial Setup
The following tests should be made with an adequate battery charge and with the power charge plug in place, and the RS232 cable disconnected. If the battery has previously been low, allow at least 15-minutes for the battery charge to build up. On power up (press and briefly hold the POWER ON button), allow a further 5-minutes for the circuitry, and LCD screen to stabilize. After stabilization, press USER, then F2 to arrive at CONTRAST. Press ENTER, and use the Up / Down keys to adjust for optimal contrast. One way to do this is to press the Up arrow until the background begins to darken and then backtrack down by pressing the down arrow once. In any case , the waveform and alphanumeric characters should both be black and stand out in strong contrast to the background Check the brightness by pressing the blue button with the Sun icon. Continue pressing. After 10-counts, it should resume to maximum brightness. If any of the above steps perform unsatisfactorily, you either have an undercharged battery, or a malfunctioning LCD display. Check with the service department (see phone numbers on Page 1 of this document), before returning the unit.
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Test and Calibration
Sequencing Test
This test will verify that the internal multiplexors are correctly sequencing information to the display. Note that much of the sequence is dependent on the previous display, so many of these steps will not work when separated from the overall context. 1. Press the USER key. The following menu bar should display at the base of the screen:
2.
In the previous screen, use CONTRAST to make any necessary adjustment, then press the SCOPE key. The following menu should display:
3.
Press the F1 key. The following menu should display.
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4.
Press SCOPE, then F2 (PROBE ADJUST). the following display should result.
5.
Press ENTER to leave the PROBE ADJUST display, then complete the Scope input using the ENTER button and Direction keys. Then press Ch A, ACV, then F3 (TREND). You should get the following menu display:
6.
Repeat the sequence for Step 6, except in the last step, press F2 (TRIGGER), instead of F3. Follow by pressing ENTER -You should get the following menu display.
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7.
Press F1 (EXIT) to leave the Trigger menu, then ENTER. Now press Ch B. The following menu should result.
8.
The previous screen shows the Channel B available selections. Click through the sequence until you get to 1mV/Psi. Then finish the other selections and click ENTER. Check that the display shows Psi units at the top left of the screen. This is a spot check on the sequence of one of the lists in this menu. You may choose to do this for the other lists too (i.e.:ACA, DCA, etc.). Press ENTER to exit with your selections from the previous screen, the press Ch A. The result should show the selections available specific to Channel A, as depicted in the following screen.
9.
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10.
Use the direction arrows to move down the menu to BEEP. Select F4 to acknowledge selection. The following screen display should result.
11.
Press CH A to return to the original Channel A menu, except this time use the direction keys to move down to the DIODE selection. Press the F4 key to acknowledge selection. The following display should result.
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Test and Calibration
12.
Press the Ch B key, then F4 to acknowledge exiting the Diode Test mode. Select Ch B a second time to bring the selection options up to the top of the menu. Then in the Channel B menu, select ON, ENTER, ACV, ENTER. You should now have a dual trace display. Press the SAVE key. This should give you the following menu selection.
13.
In the screen save menu, select SAVE, F4 (ENTER), then SCREEN 1, F4. This will save the first of the two possible saves in internal memory. Now repeat the screen save function (SAVE key), except choose RECALL, F4, SCREEN 1, F4. A screen similar to the following should result:
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14.
Press the Ch B key. Select ON and ACV, then press F4 (ENTER) to enter the command. You should get the following screen.
Battery Check
15.
In the screen shown above, use the keys F1 and F4 to separate and position the two traces from Channel A and Channel B in conjunction with the Up and Down arrow buttons. Also note the Battery symbol in this depiction. The bars of the battery will blink when the battery starts to get low. The battery symbol is replaced with a power plug symbol whenever the power cord is attached. Press the USER button, then F3 (RS-232C). Press the ENTER button. You should get the following screen menu:
16.
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Test and Calibration
17.
Select the correct baud rate for your computer and press F4 (ENTER). Refer to Appendix D for other RS-232 interface details. While still in the USER / CONTRAST Menu, select F4 to activate the POWER DOWN menu. Then press ENTER. The resulting display should be similar to the following one:
18.
19.
Use he Up/Down arrow buttons to select 10-Mins, then press F4 to enter command. Note the local time that the unit should switch off. If the unit switches off at any other time, then the internal sequencer is incorrectly set and will need to be adjusted. Note that you can continue to use the 460 in any way you choose up until it automatically powers down. This is the end of the general sequence test. If any problems were found with sequencing, other column type lists that were not included should also be checked. For general operational tests, refer to Chapters 2 and 4.
20.
Calibration
Most calibration adjustments are carried out at the service facility or factory, however the following tests and adjustments can be made in the field. If you established that the instrument or attachments are out of alignment and/or are not measuring within the confines of the specifications, call your local service representative or the number at the front of this manual for the correct address to return your parts to for test and calibration. " " Always use a known or reliable standard when making a test measurement. For instance, when testing a resistance scale, use only high tolerance parts. E.g.: +/- 1% Check that the accessories such as test leads are the correct type for the entity being measured (some test leads have their own specifications and are usually supplied with the product.
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Test and Calibration
"
Make sure that both the instrument and test leads are not close or parallel to electromagnetic sources which could be picked up by the 460 and/or the leads and which could effect readings. Be sure that the ground (Common) for the entity being measured is the true ground. Check the specifications in Chapter 1 for the scale being measured Note that probes which are internally attenuated, usually have their own adjustment procedure. Chapter 4 has an adjustment procedure for 10:1 probes.
" " "
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Maintenance
Appendix B Maintenance
This chapter covers basic maintenance for the hand-held TPI Scope Plus 460. These procedures include general inspection, use and inspection of probes, and battery check and replacement. Note that attempts to perform maintenance beyond the scope of this document, especially alterations to interior settings, may result in a default of your warranty coverage.
General Inspection
The following steps are recommended, but the sequence is not critical. If all steps are performed, and the instrument is malfunctioning, note the conditions on a label and attach it to the instrument. Prepare the unit for mailing in to the address given at the front of this document, but please call the service department before shipment. 1. Check the exterior of the instrument for damage and existence and functionality of the carrying handle and back support flap. Check the back of the instrument for any loose or missing screws, and any obvious interior rattles. Note: Do not shake the instrument vigorously. A gentle rocking is sufficient to check for loose parts. Check the display face plate for nicks and scratches that could cause interference with viewing waveforms. Check the plug sockets at the top of the instrument for discoloration or burns, etc. Check the key markings and silk screening above the display (Ch A / COM / Ch B), for readability. Connect the power adapter to the 460, and allow 10-minutes for the circuitry to stabilize. Then press USER > CONTRAST and use the arrow keys and sun icon button to adjust for optimal brightness and contrast. If the brightness and/or contrast are slightly out, the internal battery may be undercharged. If the unit has been in service for a long time and the display is very dim, you may need to replace the battery (see instructions on battery checks and replacement later in this chapter).
2.
3.
4. 5.
6.
Probes
The 460 comes with one set of probes and can be used with a number of other probes available as optional extras. Most of the probes come with their own specifications and instructions, so only general maintenance information will be included here. Please note the following points. B-1
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1.
The bandwidth of the 460 is 20 Mhz. Not all probes have this much bandwidth. If you use probes with lesser bandwidth, the measurements and waveform interpretation may be inaccurate. Check the specifications of the probes you receive before using them. The ground potential in the shield of most co-axial type probes is the same potential as the "Common" potential. This means that if you use the convenience ground outlet in the body of many probes, it will have the same effect as using a separate wire from the "COM" outlet of the 460. The normal attenuation in probes is, for all practical purposes zero, these are the probes referred to as 1:1 probes. Another commonly used probe is the 10:1 probe. The 10:1 probe is attenuated (sometimes switchable) to read only one tenth (1/10th) of the potential that the probes detect at the probe tips. The 460 has an internal ability to read 10:1 probes correctly, as long as the instrument is correctly set (SCOPE > F1 > 10:1 > ENTER) . Note that you can set up the two channels of the 460 for different probe sensitivities. The 10:1 probe requires a minor adjustment (because of the internal attenuation circuit) whenever you set the probe up, or use the same probe on a different channel. This adjustment is so that the displayed waveform will accurately represent the shape of the waveform being measured. The adjustment is usually made via a trimmer (variable capacitance) in the head of the adapter at the instrument end. Refer to Chapter 4 (10:1 Probe Compensation Adjustment), for instructions on making the adjustment.
2.
3.
4.
Battery Check and Replacement
The 460 uses a rechargeable 4.8V Ni-Cad battery (4-cells @ 1.2V, 1.4Ah). The battery should last through many recharges before losing the capacity to hold a charge. Should the latter case happen, the best option is to replace the battery. The following steps will guide you through this process. Disassembly: 1. Disconnect the power charging plug and all connectors and cables. Then check that power for the instrument is off. If the battery compartment cover is hot, you may wish to let the instrument cool before performing the next step. 2. 3. At the back of the instrument, remove the two screws near the base of the support flap. Turn the instrument over so that the battery cover and battery fall into the palm of your lowest hand. If they do not come out on their own, give a slight up and down shake to the instrument. However do not use excessive force.
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Maintenance
4.
Reverse the instrument again, so that you can see the battery connections entering the instrument. Gently pull the leads back and downwards so that the plug releases without catching onto the inside of the case. Note the battery type that you have just removed as a double check with the type you are going to replace it with. If you are going to dispose of the old battery, mark it for proper disposal. Ni-Cad batteries should not be incinerated in standard incinerators or crushed.
5.
6.
Assembly 1. The 460 uses a TPI A006 replacement 4.8V rechargeable Ni-Cad battery. Unpack and check the battery type and the existence of a 4-pin plug on the end of the leads. The battery comes uncharged and will need to be fully charged after installation. 2. Refer to Figure B-3 and install the connector into the battery compartment socket. Note that the red leads are to the right of the connector. The leading edge of the connector is best inserted slightly upward and forward. Refer to Figures B-2 and B-3, and install the battery into the compartment, connector end first. Fold the wires in a single fold to the left, keeping the wires at the top of the compartment. Check the wires are inside the perimeter of the battery case housing and replace the lid above the battery. Insert slight pressure on the lid to determine if the wires are properly folded inside. Insert the two screws and tighten down without using excessive force. Turn the unit over and insert the power charging plug. Set the instrument aside to fully charge. --Typically 12-hours for the initial charge. Refer to Chapter 2 and perform the 460 setup with special emphasis on setting up the initial contrast setting. Note that even after fully charging the batteries, a low contrast setting may make the screen difficult to read until adjusted.
3.
4.
5.
6.
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Maintenance
Use single loop U configuration between connector and battery outlet.
Fig. B-1. Pre-install Battery Wire position
Fold wire within confines of inner battery compartment
Fig. B-2 Battery Wire position after installation
Note topside position of guide bar, and location of red wires to right side.
Fig. B-3. Battery Connector position before insertion.
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Glossary
Appendix C Glossary
The following terms are pertinent to the TPI Scope Plus 460 and the environment in which it typically works. The meanings in other environments may be different to those described here. Cross references in this glossary are identified with an asterisk (*). Active Power A power measurement in Watts that is derived by multiplying the voltage portion of the signal by the current that is in phase with that voltage. A non-digitized signal such as those used to drive an oscilloscope. The product of the voltage applied times the current flow. The unit of measure is VA (Voltamperes), and the term is only applicable to Alternating Current (AC) circuits. The action by a measuring device to (on command) wait until a reading has stabilized before storing that reading and making it available for display.
Analog Output Apparent Power
Auto Hold
Auto Ranging
Ability of a measuring device to automatically select the appropriate range of measurement. A command to the measuring device (AUTO on the 460) to go from manual to automatic setting based on the magnitude of the signal being measured. The frequency range over which the instrument operates efficiently. Acronym for Cold Cathode Fluorescent Lighting. -- The type of backlighting used in several tpi instrument displays to light the back of the LCD* screens. A circuit in a measuring device which automatically resolves the difference between an ambient reference (used when the device was calibrated), and the actual operating temperature of of the measuring device. The reciprocal of resistance expressed in terms of Siemans (formally mhos).
Auto Set
Bandwidth CCFL
Cold Junction Compensation
Conductance
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Glossary
Contrast Continuity Beeper
The level difference between light and dark. Audible tone emitted from a meter when the resistance falls below a preset threshold value (typically 100 Ohms). Voltage and Current do not always happen together, often there is a difference. The difference is an angle between 0 and 90, termed F. The greater e angle, the bigger the difference between True and Apparent Power and the smaller the Power Factor. If Voltage and Current happen at about he same time, F is small, the values of True and Apparent Power are close, Power Factor approaches 1.
Cosine F
Criterion Sound Level Level
The eight hour average weighted sound level, expressed in dB, that corresponds to the maximum permitted daily exposure to noise as prescribed in national and state regulations. The ability of an instrument to acquire measurement information as it occurs, and to be able to store it, for future retrieval or transmission. Typically, the ability of an instrument to store information in non volatile memory for use later (on demand) for analysis and report generation. The temporary storage function of a measuring device which holds a displayed value when a user presses a key or button. The unit of measure expressed as dB's, used when measuring the level of sound. Every 3dB represents approximately double the power or sound level, hence 53dB is twice as loud as 50dB. dBm refers to decibels above one milliwatt. In dual input measuring devices, differential is the displayed difference between the two inputs (Input A - Input B = Differential). A function of a measuring device in analyzing the operation of a diode. The probe leads are attached to either side of the diode and the user is alerted visually and/or audibly as to the diode's integrity. The number of display units a meter or other device can indicate. For example, a 3-1/2 digit display can indicate from 0 - 1,999 and a 4-1/2 digit display can indicate from 0 - 19,999. If a meter is bi-polar it can indicate positive and negative depending on the
Data Acquisition
Data Logging
Data Hold
Decibels
Differential
Diode Check
Display Counts
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Glossary
polarity of the signal being monitored Duty Cycle The ratio of the working time to the total time of a pulse train expressed as a percent. The period of time between the start of a measurement series to the last measurement observed or recorded. The measure of electric energy whose unit is the Watt. E.g.: 1 Horsepower = 746 Watts. It is derived by multiplying the applied voltage by the current passing through the circuit A term related to temperature measurement using Infrared radiation. Errors in IR measurements can occur based on the color, shape, and presence of reflection on the measurement surface. A wide emissivity adjustment should be available on a IR thermometer to allow the user to compensate for these types of errors. Waves generated by a magnet configuration usually consisting of a coil wound around a steel core. The core is strongly magnetized when current flows through the coil. Video Monitors, power lines, and wire harnesses are a few of the devices which produce electromagnetic radiation. The ability of an instrument to listen for and capture spikes that occur in signals. The resulting captures are usually sent directly to the screen for display. An output from a meter or controller which is used to indicate when a preset measurement point has been reached or exceeded. On the tpi 460, the continuity checker is a form of Go/No Go alarm A four wire method of connecting test leads which is designed to eliminate or greatly reduce the effect of lead and contact resistance and thus permitting accurate measurements of low resistance. Acronym for Liquid Crystal Display. Liquid crystal is a liquid that is not isotopic, that is, it forms patterns when polarized. The orientation of the molecules of the liquid are arranged by the meter to form the display. Acronym for Light Emitting Diode. An electric current is passed through the diode causing illumination. When used for alphanumeric display purposes, the LED's usually have seven segments
Elapsed Time
Electric Power
Emissivity
EMF/Electromagnetic Radiation
Glitch Capture
Go/No Go Alarm
Kelvin Connection
LCD
LED
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Glossary
per digit Orange, yellow and Green are common LED colors. Load A device that is driven by the output of a meter or other measuring or control equipment. An example of a load is a resistor being measured by a multimeter. The resistor "loads" the meter since it becomes part of the measuring circuit. Integrated circuits which perform many instructions per second for functions such as mathematical equations,data storage, display updates, etc. Microprocessors are at the heart of computer accuracy, repeatability and speed. Also called CPU's (Central Processing Units). A function of a measuring device which records (saves) the highest and lowest reading it has encountered since being reset (cleared) or powered up. A device that sequences access to a communication port. Several different devices can share a single COM port on a computer if they are multiplexed. A signal that is greater than that which a measuring device can accurately or safely accept. Many meters have overload protection in the form of a fuse, or similar device, to protect the meter from overload input. Visual display alerting the user that the signal present at the meter's input is out of range. The ability of a measuring device to hold the highest reading until the user clears the display. Also known as Peak Detect. Displays the difference between the measured value and the stored value. Displays measured value as a percentage of stored value for checking component tolerances. This is the ratio of Watts to VA, or True Power* divided by Apparent Power. This can be expressed as a decimal or percentage, i.e. : PF=0.65 or PF=65%. True Power is never greater than Apparent Power, so the Power Factor is never greater than 1. Power Factor may also be expressed as Cosine F* Most probes are only mechanically different. However when they C-4
Microprocessor
Min/Max
Multiplexer
Overload
Over Range Indication Peak Hold
Relative Mode
Relative % Mode
Power Factor
Probe Select
460 User's Guide
Glossary
differ electrically they will effect metering. The most common electrical difference is a change in attenuation. tpi probes typically come with attenuations of either 1:1 or 10:1. Probe Adjust For the meter to read accurately, the DUT and input capacitances should match. Probe adjust allows a capacitance compensation to be made whenever a change of probes or oscilloscope input is made. A relative humidity measuring device which has two thermometers. One of the thermometers measures ambient temperature (dry bulb), the second measures the temperature of an element surrounded by a fibrous material saturated with water (wet bulb). Reference tables are than used to determine relative humidity. The tracking of events as they happen. To bring back from memory and display a previously recorded waveform. The smallest value a display device can indicate. For example, if a device can display 0.0 to 100.0 RPM, the smallest measurement, and therefore the resolution, is 0.1 RPM The rate at which a measuring device responds to a change in the measured variable A capacitive device that senses relative humidity The meter used with such a probe senses the change in capacitance based on the moisture encountered by the capacitor's dielectric and displays the relative humidity based on this capacitance value. A resistive device that senses relative humidity The meter used with such a device monitors the resistance of the probe which changes proportionally to the amount of moisture encountered. The meter then displays the relative humidity based on this resistive value. See "True RMS" A temperature measurement device whose resistance is proportional to temperature. A single alternating current source such as a typical AC wall outlet. Three-phase on the other hand, provides three separate alternating
Psychrometers (Wet Bulb)
Real Time Update Recall Mode
Resolution
Response Time
RH Capacitance Probe
RH Resistance Probe
RMS RTD
Single Phase
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Glossary
signals. Thermistor A resistive temperature measurement device whose resistance decreases as the temperature increases. A thermistor is a stable, compact and rugged two terminal ceramic-like semiconductor bead. A 2-wire temperature measurement sensor constructed of two dissimilar metals which form a junction. Current flows from one metal to the other in proportion to temperature. A millivolt signal is then measured by a thermometer or other display device temperature. Sound levels below this point (also called Threshold Cutoff), are excluded from dosimeter measurements. National an