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AOM5
Analog Output Module
Introduction HardwareCompatibility
The AOM5 is a high-speed analog output module provid- The AOM5 can be operated in slots 2 through 10 of the
ing four independent channels of D/A conversion. A 5OOA, 5OOl?, 556 mainframe. Up to nine AOM5 modules
or
system strobe feature, supported by two levels of data can be used in these systems for a maximum of 36 analog
latching in the D/A converter, allows all D/A channels to output channels. The AOM5 can also be used in the option
be updated simultaneously. slot of the Model 570 or 575 for up to 6 analog output
channels.
TheAOM5 D/A converters offer 13-bit resolution (12 data The AOM5 uses the voltage reference which is a part of the
bits plus a sign bit). Four output ranges can be independ- system A/D converter circuitry. In the 500~seriessystems
ently selected through software for each channel: lOV, SV, and Mode1575, the reference is located on the AMM analog
2V, and 1V. The sign bit switches the converter output master measurement module plugged into slot 1 of the
either positive or negative, so the effective full-scale reso- system. Where analog input measurements are not needed,
lution for a bipolar range is 8192 steps. Programming +OV an AOM5 can also be plugged into slot 1 of these systems.
or -0V results in the same output. Maximum nonlinearity This requires that the optional on-board voltage reference
is fl.O24%. be populated on the AOM5. This reference circuitry is ex-
plained later in this manual under the topic "Using the On-
board Voltage Reference".
The AOM5 analog output circuitry has a 5~s settling time,
and can theoretically achieve output update speeds of
2OOkHz. However, the speed of the computer limits the
rate at which successive output values can be written to the Software Compatibility
module, with a typical speed being about 6OkHz for a
1OMHz 80286-based computer. Keithley's KDAC500 software fully supports the AOM5. If
you are using third-party software, be certain that the
software is compatible with the AOM5.
High-speed operation is supported in Keithley's KDAC500
software by the ANOUTQ (ANalog OUTput Quick) com-
mand. The AOM5 analog output circuitry also offers an The AOM5 can also be programmed by accessing its
"auto-sequence" mode which can be implemented through command registers. This can be done through any high- or
PEEK and POKE commands or assembler language. This low-level language by writing directly to the AOM5
feature makes it possible to write optimized high-speed Command A (CMDA), Command B (CMDB), and Global
analog output routines. It is described later in this manual. Strobe registers which are explained later in this manual.
Document Number: 501-920-01Rev. A
Copyright Q1990 Keithley Instruments, Inc., Cleveland, OH 44139 (216)248-0400 AOM5-1
AOM5A
Analog Output Module
3
QQQ 0
B
0
I
?gure I. AOM5 Module
Specifications CAUTION
Turn off power to the data acquisition system
Channel capacity: 4 before you insert or remove any module. To
minimize the possibility of EMI radiation,
Resolution: 13 bits (12 data bits plus polarity bit). always operate the data acquisition system
with the cover in place and properly secured.
Full-scale Output Ranges: &lOV, &!W, &2V, flV
Output updating: Instantaneous update or global strobe. CAUTION
Make sure you have discharged any static
Maximum output load: 2wZ minimum. 1OOpFmaximum. charges on your body before handling the
module. You can do this most easily by simply
Settling time: 5~s to 0.01% flLSB for any step size. touching the chassis of a computer or data
acquisition mainframe which is plugged into
Maximum output update frequency: 2OOkHz agrounded,b-wireoutlet.Avoid touchingcom-
ponents or the card edge connector of the
Non-linearity: fl LSB module.
Accuracy:~lOVrange-M.15%`omV.Otherranges,M.2%
f4mV. For a compatible multi-slot data acquisition system (e.g.
Model 5OOA,5OOP, 556), remove the top cover of the
or
Temperature coefficient: ti.O025% per degree C. system by loosening the cover retaining screws located in
the upper corners of the rear panel. Slide the cover back
about one inch and then lift it off. Insert the module in the
Installation desired slot with the component side facing the system
power supply. Replace the system cover.
All features and operating modes of the AOM5 module are
programmable; there areno hardware switches to be set.
For a Model 570, install the module in the option slot with
the component side of the board facing upward. Close and
secure the cover.
AOM5-2
AOM5
Analog Output Module
For a Model 575, first attach the supplied right-angle the block and insert the bare end of the wire into the corre-
bracket to the module (see Figure 2). Plug the AOM5 into sponding hole. Tighten the screw securely to compress the
the option slot with the components facing upward, and tab against the wire.
secure the bracket to the rear panel of the system. Close and
secure the cover.
After you have attached all the desired signal wires to a
terminal block, replace the terminalblock by lining it up
with the mating pins on the module and pressing it back
End View Top View into place.
\
NOTE
,
For analog output connections, use shielded
I cable to minimize the possibility of EMI radia-
Threaded Hole tion. Connect the shield to module analog
ground. Leave the other end of the shield dis-
1
3gure 2. Model 575 Mounting Bracket connected.
Output Limitations
Connections
The output circuitry of the AOM5 is designed for fast
The four channels on the AOM5 are accessedthrough the output settling time. Because of the design, there are
quick connect terminals of J2. Each of the four outputs has restrictions as to the output capabilities of each channel.
two terminal screws: one screw for analog output and one Generally, there is an upper limit on the amount of capaci-
for analog ground. The channel connections are listed in tance and a lower limit to the resistance that can be con-
Table 1. nected across the output. To avoid possible oscillation,
output capacitance must be less than 100pF.
Table 1. J2 Connections
If it is necessary to drive a capacitive load larger than
lOOpF, a 1OOzL larger resistor must be placed in series
or
Channel with the output. This will slow down the settling time
Number somewhat, depending on the value of the capacitive load.
A wire jumper is installed on the AOM5 circuit board in
series with each output. The jumper may be removed and
replaced by a series resistor if desired. The jumpers are
labelled Wl through W4 on the component layout, and
correspond to output channels 0 through 3 respectively.
A quick-disconnect terminal block can be removed from Similar restrictions apply to the output current, which is
the module to facilitate making connections. Pull the block determined largely by the resistive component of the load
straight off the board with a firm, even pressure. Do not pry connected across the output. If the resistance is too small,
the terminals with a screwdriver or sharp object, or you accuracy will suffer. To maintain rated accuracy, the load
may damage the circuit board. resistance should be at least 2w2 at the maximum output of
flOV. Maximum current output is 5mA or less.
Each individual terminal on a terminal block consists of
a small metal block with a hole and metal compression tab If an analog output channel must drive a load with both
within the hole. To make connections to a terminal block, low resistance and high capacitance, the output must be
first strip 3/16 of insulation from the end of the wire which buffered by an external voltage amplifier.
you want to attach. Loosen the desired terminal screw on
AOM5-3
AOM5A
Analog Output Module
AOM5 Commands and Command Locations SLOT-DEPENDENTCMDA,DATAREGISTERSELECT
AND D/A CONTROL
The AOM5 is controlled by writing to the Command A
(CMDA), Command B (CMDB), and Strobe addresses for Writing to the Command A location controls the register
the slot in which the module is mounted. Programmable selection, auto sequencing, and global strobe updating of
parameters include selection of channel and range, loading the D/A converter in the analog output circuitry.
of data, auto-sequencing control, and strobe. There are no
READ modes for the AOM5. Refer to your data acquisition D/A control must precede any change in range register
system hardware manual for the addresses associated with data. This write resets the register auto-sequencing circuit
the slot where the AOM5 is mounted. to the proper register. The lower four bits represent the
register to be written first. Bits D5 and D6 represent the last
channel for auto sequencing of the data written to the
Table 2. Slot-Dependent Memory Locations (hex) output data registers (registers 0 through 7). Setting bit D7
enables global strobe (seebelow) to update analog outputs
500,570,575 GPIB simultaneously.
I I
SLOT CMDA CMDB CMDA CMDB
SLOT-DEPENDENT.CMDB, D/A DATA AND RANGE
1" xxx80 xxx81 0 1 DATA
2 xxx82 xxx83 2 3
3* xxx84 xxx85 4 5 Through the use of register auto sequencing, the various
4 xxx86 xxx87 6 7 D/A control registers can be filled by writing repeatedly to
5 xxx88 xxx89 8 9 the CMDB register. Range registers are filled first, in de-
6 xxx8A xxx8B A B scending order from 3 to 0. After filling the range registers,
7 xxx8C xxx8D C D the DAC data bytes are written for each channel, LSB first.
8** xxx8E xxx8F E F The DAC requires two write operations to supply the 13
9 XXX90 xxx91 10 11 bits necessary for data and polarity information. The range
10 xxx92 xxx93 12 13 registers are only set once, until a write to CMDA points to
the range registers again, and thedata-registers are con-
* = Model 575 Physical Slots tinuously updated to allow variable output. When the
** = Model 570 Option Slot global strobe update feature is not enabled, the output
xxx = First three digits of IBIN address, e.g. "ClT
channel is automatically updated upon receipt of the sec-
ond byte of data. When the global strobe update feature is
enabled, data is not latched into the conversion register of
the D/A converter until receipt of the global strobe signal.
Table 3. AOM5 Command Locations and Functions
Twelve of the available 16 registers are implemented in this
Circuitry.
Read Functions:
COMMAND FUNCTION Initially, a D/A control is issued which must select one of
the four range registers, register 12,13,14, or 15 for channel
CMDA None 3, 2, 1, or 0 range, respectively. Additionally, the D/A
CMDB None control must select the last channel for auto sequencing,
and either enable or disable the global strobe update fea-
Write Functions: ture.
COMMAND FUNCTION
After the D/A control is issued, the D/A data is loaded.
CMDA Data register select, D/A Control The command circuitry selects the appropriate range reg-
CMDB D/A Data and Range ister, and register control is relinquished to the auto-se-
xxx9D Strobe (update all outputs) quencer. The range registers are filled with the proper
range data. The auto sequencer drops to the output data
AOM5-4
AOM5
Analog Oufpuf Module
registers. D/A output data is written, and the sequencer where counts = DAC data, volts = desired voltage output,
automatically "points to" the next register to be written. and range = the output range setting for the particular
The data is written LSB first, then MSB, going from chan- channel. The digital data must be adjusted to include the
nel 0 to channel 1, then 2, then 3. If the global strobe update sign bit (the D7 bit in the MSB of the data). This may be
feature is disabled (in the D/A control word) the output of accomplished by adding 128to the MSB if negative voltage
the D/A converter is updated immediately upon receipt of output is desired.
the MSB of data (including the polarity bit). If the strobe
input is enabled, the data is not latched into the output
registers of the D/A converter until receipt of the active xxx9D (STROBE)
low strobe input. GLOBAL ANALOG OUTPUT UPDATE!
The strobe command is used to synchronously update all
To determine the digital value corresponding to a given analog output channels. Thestrobe feature is global, affect-
voltage, it is necessary to know the output range setting of ing all D/A channels in a system whose global strobe
the DAC. Since the AOM5's 13-bit converters are organ- feature has been enabled. Any analog output whose global
ized as 12 data bits plus sign bit, there are actually 4096 strobe has been enabled, and whose data has not been
possible voltage levels to be programmed, specified with changed since the last global strobe was issued, will not
digital values of O-4095. 13-bit resolution results from change its output voltage.
setting the polarity bit for positive or negative output. The
full-scale value is the nominal full-scale value minus 1 LSB,
and the resolution is 1 part in 4096, or about 2.44mV on the Writing to the global strobe command location causes the
10 volt range. The DAC counts for a particular output can STROBEline to go active low, and allows global update of
be calculated as: all DAC outputs if the analog output circuit is so config-
ured.
COUNTS = ABS [ ( VOLTS / RANGE ) x 4096 I
AOM5-5
AOMSA
Analog Output Module
DATA
CHAN 0
CHANNEL 0
CHANNEL 1
CHANNEL 2
CHANNEL 3
CH3OUT-
MDA. STROBE CMDS, DATA/RANGE
(WRITE ONLY) (WRITE ONLY)
2v
J
TO AID
IV
a MUX
RANGING
CMDA (WRITE) D/A CONTROL
D7 D6 D5 D4 D3 D2 Di DO
Last channel for auto-sequencer
Global strobe: Enable (0), Disable (1)
CMDB (WRITE) D/A DATA OR RANGE
Data Register Format
MSB LSB
D7 D6 D5 D4 D3 D2 Di DO D7 D6 D5 D4 D3 D2 Dl DO
/ I ' L :X$+:2 bits
Sign bit: Negative (i), Positive (0)
Range Register Format
D7 D6 D5 D4 D3 D2 Dl DO
I I
Range: 1OV (0), 5V (I), 2V (2), 1V (3)
Unused
`igure 3. AOM5 Block Diagram and Register Funcfions
AOM5-6
AOh4.5
Analog Output ModuZe
COUNT SEQUENCE
CMDB WRITE REGISTER TABLE
-4-
REGISTER NUMBER DISCRIPTION
---- + Last Channel = 0
:
0 Channel 0 LSB I
1 Channel 0 MSB
---- -b Last Channel = 1
2 Channel 1 LSB :
3 Channel 1 MSB
4 Channel 2 LSB Last Channel = 2
5 Channel 2 MSB
6 Channel 3 LSB
7 Channel 3 MSB Last Channel = 3
8 Not Used
9 Not Used
10 Not Used
11 Not Used
12 Channel 3 Range -+1
13 Channel 2 Range -+1
14 Channel 1 Range -+1
15 Channel 0 Range -+
1
L----b----
SROBE (WRITE) UPDATE OF OUTPUTS, ADDRESS = xxx9D
The GLOBAL STROBE can be used to simultaneously update all D/A outputs in the system. This includes all
output channels on all D/A cards in the system which have been programmed to respond to GLOBAL
STROBE.
To enable the AOM5 to respond to GLOBAL STROBE, write a 1 to bit 7 of the AOM5 CMDA register.
OUTPUT DATA
Calculate the data value (number of bits) for a desired output voltage as follows:
DATA VALUE = (ABSOLUTE VALUE (VOLTAGE) I RANGE) X 4096
Set bit 13 to 0 for positive output, or 1 for negative output. See CMDB for information on writing data to AOM5
data registers.
AOM5 BZock
Diagram and Register Functions (Cont.)
AOM5-7
AOMSA
Analog Oufput Module
Automatic Register Sequencing Table 4. AOM5 Automatic Sequencing
The AOM5 analog output circuitry includes an automatic
incrementing circuit for the analog output range and data Zegister
registers. The incrementing circuitry aids in high-speed VO. Description Sequence
output progr amming. The following information will be
useful for generating analog output by directly accessing
the CMDA and CMDB registers. These operations are
0
:
Channel
Channel
Channel
0 LSB data
0 hEB data
1 LSB data
1i
normally handled by KDAC500. 3 Channel 1 MSB data
4 Channel 2 LSB data
Channel 2 MSB data
ii Channel 3 LSB data
Generally, standard (non-auto sequenced) analog output 7 Channel 3 MB data
is generated by first writing register select information to
CMDA, followed by writing the corresponding data to
CMDB. These steps are repeated until all the necessary
range and output data have been written for a desired
12 Channel 3 range
channel. For channel 0, a typical sequence might be as fol- Channel 2 range
lows: ?I Channel 1 range
15 Channel 0 range
1. Write "15" to CMDA to select the channel 0 range
register.
2. Write the desired range to CMDB.
3. Write "0" to CMDA to indicate that the following data
will be analog output low-order byte for channel 0. Note that entry points in the loop may be range informa-
4. Write the channel 0 low-order data byte to CMDB. tion or output data. As an example, if the initial write to
5. Write "1" to CMDA to indicate that the following data CMDA is "14", the analog output circuitry would assume
will be analog output high-order byte for channel 0. that the next byte is the channel 1 range, followed by the
6. Write the channel 0 high-order data byte to CMDB. channel 0 range, the channel 0 least significant data byte,
(Note that bit D7 governs the polarity of the output.) the channel 0 most significant data byte, and so on. Once
7. Write to the GLOBAL STROBE location (xxx9D) to up- the sequence moves out of the range registers, it will cycle
date the channel 0 output. continuously through the channel registers without re-
turning to registers 12 through 15.
Automatic register sequencing automates several of the If the first control byte written to CMDA is 0 through 7, the
write operations listed above. It first requires that a control auto sequence logic will expect that the next bytes written
byte be written to CMDA (seeTables 2,3, and 4). This byte to CMDB will be data. The loop will not enter the range se-
must include the register selection and last channel desired lection registers at all.
for auto sequencing. The most significant bit (MSB) of the
byte must be 1 to disable the global strobe function.
If the first control byte written to CMDA specifies that
Next, data must be written to CMDB. This data may be channel 0 is the last channel for auto sequencing, then the
range data or the output low-order or high-order data byte, loop will run only through registers 0 and 1 (channel 0 LSB
according to the information written to CMDA. The infor- and MSB data) and not include registers 2 through 7. This
mation written to CMDA also sets the "entry point" in the path will confine output to channel 0 and permit the maxi-
auto-sequencing loop, thus establishing the expected or- mum output speed from channel 0.
der of subsequent bytes written to CMDB. The auto se-
quence logic assumes that the next bytes will conform to
the following sequence: The GLOBAL STROBE is typically disabled for auto se-
quencing. This enables the output of a channel to be up-
dated as soon as the MSB data for the channel is written to
the channel MSB register.
AOM5-8
AOM5
Analog Output Module
Calibration Using the same reference voltage for generating and me-
tering test voltages also has error canceling advantages.
This section contains general field calibration information For example, if the reference voltage is slightly off, both the
for the AOM5. The procedures given are not necessarily as output voltage to an experiment and the resulting voltage
accurate as factory calibration. Also, the procedures given reading by the A/D will both be off by the same percentage
assume a certain amount of expertise on the part of the including the polarity of the error. Calculations which ratio
user. If you are not familiar with calibrating equipment, do the drive voltage to the measured voltage will cancel the
not attempt calibration. The procedures in this section error terms due to inaccurate reference voltage, and result
assume that you are familiar with general module opera- in a more accurate experiment result. The system reference
tion. Refer to the appropriate manual for details on cali- must be used where it is present, i.e. when an A/D module
brating each module. is in the system.
The only calibration necessary on the AOM5 is to adjust the For caseswhere no A/D is used in the system, a reference
+lO and -10 volt reference voltage buffer amplifiers. The voltage must be provided to the AOM5 for proper opera-
voltage reference used by the AOM5 is the system +lO volt tion. The user may install components Ul, RI, R2, and R3
reference, which is typically provided by the AMM2 or on the AOM5 to generate a +lO volt reference. If more than
AMMlA A/D converter modules. The output voltage one AOM5 is to be installed into a system, only one AOM5
accuracy of the AOM5 is affected by the accuracy of this needs these parts installed. This one reference circuit will
reference, so it may be desirable to calibrate the AMM2 or provide the 10 volt reference for any other AOM5 in the
AMMlA module first. system. These parts must be removed if an A/D module is
later installed in the system, since the two references will
conflict.
The calibration of the AOM5 proceeds as follows:
1. Measure the 10 volt system reference on the AMM2 or
These parts may be ordered from Keithley Instruments
AMMl A by attaching the voltmeter (+) lead to TI'7, and Repair Department by requesting the following Keithley
the voltmeter (-) lead to the analog ground test point
part numbers (see Table 5):
TP4. Note this voltage reading for use later.
2. Connect the voltmeter (+) lead to TPl on the AOM5, and
the (-) lead to TP2 on the AOM5. Adjust pot R12 for a Table 5. Components, On-board Voltage Reference
voltmeter reading identical to the reading obtained in
step 1. Keithley
3. Connect the voltmeter (-)lead toTIYpntheAOM5, and Des&. Part No. Description
the (+> lead to TP3 on the AOM5. Adjust pot R13 for a
voltmeter reading identical to the reading obtained in Ul IC-677 IC, TL431CL.P Adjustment
step 1. Shunt Regulator
RI R-76-1K Resistor
R2 R-263-6K Resistor
Please note that R12 must be adjusted first, as it affects both R3 R-263-2K Resistor
the voltage at TP2 and TP3.
Theory of Operation
Using the On-board Voltage Reference
Refer to schematic drawing 501-236 for the following dis-
The AOM5 is supplied from the factory without a built-in cussion:
voltage reference because the AOM5 is typically used in a
system containing either an AMMlA or AMM2 A/D
converter module. The AMMlA and AMM2 provide a Each of the four outputs function identically, and only the
very high quality reference voltage to the system, so anon- channel 0 output part references to the schematic are
board AOM5 reference is unnecessary. included below. The analog portion of the circuitry on the
second sheet of the schematic drawing is described first.
AOM5-9
AOM5A
Analog Output Module
The development of a specific output voltage begins with The command decoding circuitry is on sheet 1 of the
the selection of either the +lO volt or -10 volt reference schematic. U5 buffers some of the data and control lines to
voltage by the analog switch U19. If a positive output prevent excessive bus loading. The output of the 4-bit
voltage is desired, the -10 volt reference voltage is used, counter U8 represents the number of the control register
and vice versa. U19A is turned on by a low logic level on its which will be used on the next data write to CMDB. The
pin 1 when a negative output voltage is desired, and U19D output of U8 is decoded into the various write enable
is turned on by a low logic level on its pin 8 when a positive pulses for the data latches of the schematic by U6 and UlO.
output voltage is desired. The selected reference voltage is When data is written to CMDA, bits DO,1,2, and 3 load the
buffered by amplifier U31A and fed into the reference counter U8 and bits D4,5,6, and 7 are stored in U7. Every
input of the multiplying D/A converter U21. The multiply- time a write is performed to CMDB, magnitude compara-
ing D/A converter functions by multiplying the 10 volt tor U9 compares the output of counter U8 with the data
reference input by the digital number programmed by the previously latched into D5 and D6 of U7 to determine if the
computer. The digital value programmed represents a last register has been filled. If a match is determined, the
number between 0 and 0.99976.Amplifier U27A is part of output of U9 causes the counter U8 to be cleared, thus
the multiplying circuit, and the overall output of the multi- resetting the CMDB register pointer to the Channel 0 LSB
plying D/A converter circuit is at pin 1 of U27A. The register. This reset occurs at the conclusion of the CMDB
voltage at this point always has a span of 0 to +9.9976 or 0 write pulse.
to -9.9976 volts. The resistor divider formed by R19, R23,
R27, and R31 and analog switches U23A through U23D
form the range selection circuitry. One of the four analog Components Ul, Rl, R2, and R3 are not installed at the
switches is on at a time, and selects a tap on the resistor factory, and are normally not needed. Please refer to the
divider which divides the output of U27A by 1,2,5, or 10. section of this manual, "using the Onboard Voltage Refer-
This results in a span of 0 to 10,5,2 or 1 volts, respectively, ence".
at the input of U28A, the output amplifier. Capacitor C8,
combined with the voltage divider impedance and R35,
R39, and R43, provides filtering for the signal to help Calibration of the analog output circuit is not necessary
remove glitches when the D/A converter output voltage is other than the calibration of the +lO volt and HO volt
changed. The output of U28A drives the output connector reference voltages (described in the AOM5 calibration
directly. A wire jumper, Wl, on the circuit board provides procedure).
alocationforconnectingaresistorinseries with theoutput,
if needed.
Troubleshooting
The +lO and -10 volt references for all four output channels Any observed or suspected problem with a system or
come from a common set of reference amplifiers, U2 and module may be the result of malfunctions in any part of the
U3. Refer to sheet 1 of the schematic. The 10 volt systemref- system. A hierarchy of possible problem areas is listed
erence(lOVRBF),andsystemgroundreference (AN_COM) below. The list should help you apply an organized ap-
come from the system baseboard on Jl, and go to a differ- proach to troubleshooting, starting with software and
ential amplifier circuit comprised of U2, R4, R5, R6, R7,10, working toward a specific module. It assumes that your
and Rl2. This amplifier inverts the reference voltage to system and software have both worked properly in the
provide the AOM5 -10 volt reference, and isolates the past. If you have spares, you can most quickly verify a
baseboard AN-COM ground reference from the AOM5 system component through simple substitution. Check
output ground reference. C24 provides a low AC output your data acquisition system manual or computer docu-
impedance. Components C2, C26, and R48 stabilize the mentation - they may contain additional instructions on
feedback loop around U2. An inverting amplifier com- troubleshooting.
prised of U3, C3, C25, C27, R8, R9, Rl 1, R13, and R49 makes
the +lO volt reference signal.
Faulty software or applications programs'- If you have
completed a new program which does not work as antici-
A power-up reset circuit made up of U4 and the associated pated, review the program design and be certain that it
components resets all the bits in the D/A converter regis- actually functions as you assume. If a program which had
ters to 0 when the power is first applied, which results in an been running properly begins to behave erratically, either
output of 0 volts on all channels. the supporting software package or the application pro-
AOM5-10
AOM5
Analog Output Module
gram may have been corrupted. This may occur through There is a maximum permissible length specified for inter-
disk media failures, power supply problems, hardware face cables. Exceeding the length will also introduce prob-
failures, or operator error. lems. You may note erratic operation of the computer,
corrupt data, or a failme of the indicator lamps on the data
acquisition system to light.
Verify your software package against a back-up copy or
the original diskettes. If the software is questionable, you
should reinstall the software from the original diskettes or Defective data acquisition mainframe -A mainframe de-
known-good copies. Likewise, your applications program fect can affect any and all data acquisition functions. Main
should be restored from backups if a problem develops. areas include the motherboard logic and connectors, the
Note that it is crucial to back up important software and expansion slots, and the power supply. In the case of a
programs. Ideally, you should make at least two copies, completely dead acquisition system, always check any
and store one in a location away from your work site. fuses and cabling which carry power.
Application programs should be backed up regularly as
they are being developed. Printouts of program listings
may also be desirable. An individual slot may also be bad. A known good module
can be tried in various slots to determine the condition of
individual mainframe slots.
Faulty computer system - A malfunctioning computer or
peripheral can affect the data acquisition software and
hardware, ranging from minor problems to total failure. Defective module(s) in general - A failure in a module's
These problems may be continuous or intermittent. If you address, data, or control circuitry can affect other modules
suspect your computer, remove the data acquisition inter- if the malfuctions ultimately reach the data acquisition
face and run any diagnostics which came with the system motherboard or power supply. You may be able to locate
to verify its performance. Also try running other software a faulty module by removing modules individually until
with which you are familiar. Pay close attention for any the problem clears.
erratic behavior of the software which may indicate hard-
ware problems.
The master A/D module in slot 1 is a special casebecause
it processes data from all analog input channels. Any
Defective interface - A malfunctioning data acquisition analog input involves its global multiplexer, program-
interface can prevent the computer from booting up and mable gain amplifier, and A/D converter. If only the
operating properly, or it can affect only the data acquisition analog input functions are faulty, you should also consider
system. Some graphics, mouse, and networking adapters the master A/D module. Use a known-good A/D module,
conflict with data acquisition interfaces as a result of both or first verify your A/D module for proper operation
using the same addresses or interrupts. The system oper- before troubleshooting another analog module.
ates properly with one of the cards in place, but diagnostic
error messages or other problems result with both cards
plugged in. You can usually determine incompatibility by Analog output normally relies only on circuitry within an
tryingeachsuspected card individually, and then together. analogoutputmoduleunlessdocumentationforthemodule
Such incompatibility can often be overcome through switch states otherwise. The AOM5 modules uses the 1OVpreci-
settings, configuration changes, or minor modifications to sion reference on the AMM module. If you note inaccurate
the hardware. output levels from the AOM5, the AMM module may need
to be calibrated. Digital input and output are also per-
formed wholly on a single module, with the exception of
Defective data acquisition interface cable -The cable car- the PlMl and PIM2 power control modules. The PIM
ries essential power, control, or data signals. Open conduc- modules use an external board and solid state relays. These
tors in a cable will disrupt the process. Cable shorts, should also be considered in situations where PlM mod-
especially in lines carrying system power supply voltages, ules are suspected of being faulty.
may cause a total shutdown of the computer or data
acquisition mainframe. If these problems exist, try discon-
necting the interface cable from the computer and data ac- In troubleshooting modules, use a software package with
quisition system. which you are familiar to write a few simple test programs
for the suspected module. Elaborate programs should
AOM5-11
AOM5A
Analog Output Module
generally not be used. They may contain their own errors List of Replaceable Parts
which mask problems with the hardware.
Table 6 contains replacement parts information. Parts are
listed alphanumerically in order of their circuit designa-
If a suspected module does not respond as expected, you tions. A component location drawing and schematic dia-
may assume that the module requires calibration or is gram for the AOM5 are found at the end of the manual.
defective. If a module has no calibratable components, a
problem at this point will normally indicate a failure
within the module. Ordering Information
c
To place an order, or obtain information concerning re-
Defective AOM5 module - An AOM5 can be checked by placement parts, first contact the Keithley customer service
running a few simple programs which test individual department: (216) 248-0400.When ordering parts, include
features of the module. The CMDA and CMDB registers the following information:
can also be exercised to determine correct operation of the
module. See information elsewhere in this manual. 1. Model Number
2. Serial Number
3. Part Description
A skilled technician who has accessto electronic test equip- 4. Circuit Designafion (if applicable)
ment may be able to troubleshoot individual circuits on a 5. Keithley Part Number
module to isolate the faulty parts. A full parts list and
diagram set are included with each module to aid the
technician.
If an additional instruction manual is required, order the
manual package (Keithley Part Number 501-920-00Rev *).
The manual package contains an instruction manual and
If a defective component is found, replacement parts may any applicable addenda.
be obtained from Keithley. If factory service is desired, the
module may be returned for repair. All Keithley-manufac-
tured systems and modules are warranted against defects
in material and workmanship for a period of one year. For
information on replacement parts or factory service, see
the Parts List section of the appropriate manual.
NOTE
If a calibratable module which had been work-
ing accurately suddenly becomes inaccurate by
more than a few percent, the problem is more
likely a malfunction and not a calibration prob-
lem. If you cannot calibrate the hardware after
two attempts, you should return it to Keithley
for repair or calibration at the factory.
AOM5-12
AOM5
Analog Output Module
Table 6. Parts List - Model AOM5 Analog Output Module
Part No. Quantitv Title Designation
C-365-.1 14 Cap, .luF, 20%, 5OV,Ceramic Cl, C12...C25
c-64-1ooP 4 lOOpF, lo%, lOOOV,Ceramic C2, C3, C27, C28
C-64-22P 8 Cap, 22pF, lo%, lOOOV,Ceramic C4...Cll
CS-521-4 1 Corm, Strip, 8 Pin J2
CS-553 3 Corm, Test Point Tl?l...Tl?3
IC-173 1 IC, Voltage Comparator, LM311N u4
IC-182 1 IC, Decoder/Demux, 74LS138 UlO
IC-186 2 IC, Hex Inverter, 74LSO4 u13, u15
IC-190 3 IC, 2 to 4 Line Decoder/Demux, 74LS139 U17, U18
IC-203 2 IC, 18V OP-Amp, 308AN u2, u3
IC-215 1 IC, Quad 2 Input Pos AND, 74LSO8 u5
IC-246 2 IC, 18V O&Amp, 353 U31, U32
IC-267 1 IC, 8 Ch CMOS Analog Multi, 6108 U33
IC-272 1 IC, 4Bit Counter, 74LS163A U8
IC320 6 IC, SPSTCMOS Analog Switch, DG211 U19, U20, U23...U26
IC-366 5 IC, 4 Bit Bistable Latch, 74LS75 u7, Ull, u12, u14,
IC-389 1 IC, 4BIT Magnitude Comparators, 74LS85 u9
IC-504 4 IC, Dual JFET O&Amp, 412 U27...U30
IC-678 2 IC, 12-Bit DAC, AD7537JN u21, u22
IC-724 1 AOM5 PAL, MME!OLlO U6
J-3 4 Jumper, Circuit Wl...W4
R-176-10.7K 1 Res, 10.7K, .l%, 1/8W, Metal Film, T2 R47
R-263-1OK 10 Res, lOK, .l%, 1/lOW, Metal Film R4...R9, R19...R22
R-263-2K 8 Res, UC, .l%, l/lOW, Metal Film R27...R34
R-263-6K 4 Res, 6K, .l%, l/lOW, Metal Film R23...R26
R-76-39K 1 Res, 39K, 5%, 1/4W, Composition or Film R14
R-76-4.7K 1 Res, 4.7K, 5%, 1/4W, Composition or Film R18
R-76-47OK 1 Res, 47OK,5%, 1/4W, Composition or Film R17
R-88-l .82K 4 Res, 1.82K, I%, 1/8W, Metal Film R39...R42
R-88-22.1 2 Res, 22.1,1%, 1/8W, Metal Fihn RlO, Rll
R-88-3.16K 4 Res, 3.16K, l%, 1/8W, Metal Film R43...R46
R-88-37.4K 1 Res, 37.4K, l%, 1/8W, Metal Film R15
R-884.99K 5 Res, 4.99K, l%, 1/SW, Metal Film R16, R35...R38
R-88-470 2 Res, 470,1%, 1/8W, Metal Film R48, R49
RF-28 1 Diode, Silicon, lN4148 0X-35) Dl
RF-89-200 2 Pot, 200,10%, .75W, Non-Wirewound R12, R13
MC-334 1 Warning Label
501-920-00 1 Manual Package
AOM5-13
lJ1 ,F?l,FQ,R3 TO BE USER INSTALLED -/
I I
I I
I/ / I
Using the AOM5 Module
with KDAC500
The following notes describe (CONFIG) table according to the
general techniques for using the AOM5's slot position and the chan-
AOM5 Analog Output Module. The nel being used. The AOM5 output
AOM5 will normally be used to channel name used in the example
apply a voltage to some other programs is "OUTCHAN". Like-
electrical, electronic, or electro- wise, the analog input channel name
mechanical device. Typical uses used in Example 4 is "LNCHAN".
include biasing, excitation, or
driving equipment whose function, If you are using another software
position, or other performance para- package, consult your software
meters change in response to a documentation for operating modes
control voltage. and commands. In most program-
ming languages, it is also possible to
The supplied program examples get the equivalent of foreground
for these applications are oriented commands by writing directly to the
around BASIC and the foreground/ AOM5 CMDA, CMDB, and STROBE
background output commands in command registers.
Keithley's KDAC5OO/I software. A
foreground output command writes
a single value, previously stored as a Output Current
variable, to a chosen AOM5 channel.
A background output command Compliance
sequentially writes the elements of a The AOM5 has a maximum output
memory-resident KDAC500 array to drive current of five milliamperes.
the desired channel at a rate set by Where an application requires
KDAC5OO'sprogrammable greater drive power, connect the
interrupts. AOM5 output to a suitable current
amplifier or programmable analog
The channel input/output names power supply. In this case, the
(IONAMEs) must be set up in the AOM5 drives the amplifier, which
KDAC500 hardware configuration drives the load.
DAC
Using the AOM5 Module
with KDAC500
Ramped Output
Output ramps can be pro-
V Out with grammed by using the background
greater current output (BGWRITE) command to
capability 060 write a KDAC500 array to the de-
0.0
A sired AOM5 channel.
First, the ARMAKE must be used
v out to allocate the array. A FOR-NEXT
loop is then set up to:
I Programmable analog
AOM5 Module power supply (a) linearly increment a data value
and an array position index,
Figure 1. Boosting Drive Current
fb) place the data into the
KDAC500 array at the correspond-
ing index with ARKJT,
Initializing the AOM5 voltage is programmed, or until the
The AOM5 outputs will auto- system is reinitialized. Other I/O
commands may be executed earlier (c) repeat until the array is full.
matically initialize to 0 volts when a
system containing the module is or later in the program without
affecting the AOM5 output level. The loop may also apply scaling
switched on. The KDAC500 or offset calculations to the data to
HARDINIT utility, which can be achieve a desired offset and slope for
executed through the computer's Note that where the desired
the ramp. Further, the data values
AUTOEXEC.BAT file, is not output voltage does not fall exactly
may be calculated as voltage, cur-
required to initialize the AOM5 at on a bit boundary, the actual output
rent, percent of full scale, or raw
power-up. However, HARDINJT voltage will be a maximum of 1 D/A
D/A counts so long as the appro-
may be used to initialize other bit lower than programmed. For
priate engineering unit flag is used
digital or analog output modules instance, programming 6.43V will
in ARFUT. The maximum resolution
that lack a power-on reset. result in 6.428V.
The KDAC500 command KDINIT
will return all AOM5 outputs to 0
volts anytime it is called within a
program. This is an easy method for 10 ` Program 6.43V output with foreground write
resetting all analog and digital 20 ' Set AOM5 for +/-1OV range
outputs to 0 immediately before 30 CALLKDINIT
terminating a program. :
: (BASIC and/or KDAC500 commands)
400 dIM VOuT!(l)
Programming a 410 VOUT!(O)=6.43
Continuous Voltage 420 CALL FGWRITE'("outchan", vout!(), "c.volts", "nt")
Many applications will require the
AOM5 to be programmed and held : (BASIC and/or KDAC500 commands)
at a specific voltage level while other
tests are conducted. This may be 900 CALLKDINrr
accomplished most easily by 1OOOEND
executing a foreground output
(FGWRlTE) command. After the Example 1. KDAC500/1 Foreground Write
foreground write, the AOM5 output
will remain constant until another
Using the AOM5 Module
with KDAC500
the AOM5 is 8192 steps for any bi- To write the array to the AOM5, Output of Periodic or
polar output range. Careful selection set up an INTON command, being
of AOM5 range wiI.I provide opti- carefuI that the specified interrupt Complex Waveforms
mum resolution for any output interval is adequate for the computer Periodic and complex waveforms
signal. type and number of background are handled in a fashion similar to
tasks. When the program runs, the ramps, except that the FOR-NEXT
After the array has been created, a output ramp wiB begin when the loop contains a mathematical
BGWRITE command must be set up INTON command is executed. The equation to calculate the output
for the desired AOM5 channel. Anv BGWRITE command may be given a data. The equation may be linear or
other background commands shoid cycling parameter for continuous non-linear in order to generate
also be inserted at this point in the output or n repeats. ramps, curves, periodic waves,
program. random patterns, or combinations
thereof. Synthesizing a single cycle
of the wave form is usually
adequate. The BGWRITE command
10 ' Output a ramp from 0-1OV in 4.096 set cycling parameter can be set to
20 CALLKDINIT output a specific number of cycles,
or for continuous recycling.
: (BASIC and/or KDAC500 commands)
:
100 CALL ARMAKE'f"outarray%", 4096., "outchan") Output of Data Acquired
110 DIM BITVAL%(l)
120 ' with an AMMlA or
130 FOR D!=l TO 4096! AMM2
140 BITVAL%(O)=D!