Rockwell Automation 1756-XXXX ControlLogix Analog I/O Modules - Manual (Page 234)

234 Publication 1756-UM009C-EN-P - December 2010
Chapter 11 Calibrate the ControlLogix Analog I/O Modules
Difference of Calibrating
an Input Module and
an Output Module Although the purpose of calibrating analog modules is the same for input and
output modules, to improve the module’s accuracy and repeatability, the
procedures involved differs for each.
• When you calibrate input modules, you use current, voltage, or ohms
calibrators to send a signal to the module to calibrate it.
• When you calibrate output modules, you use a digital multimeter
(DMM) to measure the signal the module is sending out.
To maintain your module’s accuracy specifications, we recommend you use
calibration instruments with specific ranges. The table lists the recommended
instruments for each module.
Module Recommended Instrument Range
1756-IF16 & 1756-IF8 0…10.25V source +/-150 µV voltage
1756-IF6CIS 1.00…20.00 mA source +/-0.15 µA current
1756-IF6I 0…10.00V source +/-150 µV voltage
1.00…20.00 mA source +/-0.15 µA current
1756-IR6I
1.0…487.0
Ω
resistors
(1)
+/-0.01%
(1) We suggest you use these precision resistors.
KRL Electronics - 534A1-1R0T 1.0 Ohm 0.01% / 534A1-487R0T 487 Ohm 0.01%
A precision decade resistor box also can be used that meets or exceeds the required accuracy
specifications. You are responsible for assuring that the decade box maintains accuracy by periodic
calibration.
1756-IT6I & 1756-IT6I2 -12 mV…78 mV source +/-0.3 µV
1756-OF4 1756-OF8 DMM better than 0.3 mV or 0.6 µA
1756-OF6VI DMM with resolution better than 0.5 µV
1756-OF6CI DMM with resolution better than 1.0 µA
IMPORTANT
Do not calibrate your module with an instrument that is less
accurate than those recommended (for example, calibrate a
1756-IF16 module with a voltage calibrator of greater than
+/-150 µV accuracy), to avoid anomalies.
• Calibration appears to occur normally but the module gives
inaccurate data during operation.
•A calibration fault occurs, forcing you to abort calibration.
•The calibration fault bits are set for the channel you
attempted to calibrate. The bits remain set until a valid
calibration is completed.
In this case, you must recalibrate the module with an
instrument as accurate as recommended.