Rockwell Automation Allen-Bradley 1794-IRT8K, User Manual

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Publication 1794-6.5.12 - September 2011
46
Calibrate Your Module
3. Initiate a write to the module with the appropriate value in the EDT
command location (write word 3, bits 00…15), as shown above.
4. Monitor the EDT response location (read word 11 bits 00…15) for an
echo of the EDT command. Depending on which command you sent, it
should show 241X Hex.
If the EDT response word reads 80FF (hex), repeat the step 3. Make
sure that sufficient time is allowed for the module to respond to your
request. If there is no change, calibration has failed. Check the wiring
and try again.
5. Set the precision millivolt source to the value required for a gain of 2.
Repeat steps 3 and 4 for gain 2. Repeat for each gain setting.
6. When all offset calibrations are successful, proceed to the gain
calibration.
Gain Calibration
After completing the offset calibration, proceed with the gain calibration.
1. Connect a precision millivolt source across each input channel. Set the
source to 320.00 mV for a gain of 1. Connect all (L) signal terminals
together and attach to the positive lead from the precision voltage
source. Connect all (-) signal terminals together and attach to the
negative lead.
8 -10.00 + 0.008 mV 2413 9235 05
0 … 7
3
16 -9.00 + 0.004 mV 2414 9236 05
0 … 7
4
32 1.000 + 0.002 mV 2415 9237 05
0 … 7
5
EDT Commands for Offset Calibration
All Channels Single Channel
EDT Command
EDT
Command
Dec. or Hex
Bits 8
…
15
EDT Command
Data
Dec. or Hex
Gain
Selected Input (mV) Hex Decimal Bits
4
…
7
Bits
0
…
3