Rockwell Automation 1794-IRT8XT FLEX I/O Thermocouple/RTD /Millivolt Input Module User Manual - Manual (Page 52)

Publication 1794-6.5.12 - September 2011
40 Calibrate Your Module
Tools and Equipment To calibrate your Thermocouple, RTD, and mV input module, you will need
the following tools and equipment:
Calibrate Your Input
Module
When using remote I/O, before calibrating your module, you must enter
ladder logic into the processor memory, so that you can initiate block transfer
writes (BTW) to the module, and read inputs (BTR) from the module.
To manually calibrate the module:
1. Apply a reference to the desired input(s).
2. Send a message to the module indicating which inputs to read and what
calibration step is being performed (offset).
The module returns a response which echoes the message sent to the
module. The module stores this input data.
3. Apply a second reference signal to the module.
4. Send a second message indicating which inputs to read and what
calibration step is being performed (gain).
The module computes new calibration values for the inputs and returns
a response which echoes back the message sent to the module. If the
calibration cannot be completed, the module returns a fault message.
Tool or Equipment Description
Precision Resistors High Precision Resistors:
383 W, 0.01%, 5ppm/°C
100 W, 0.01%, 5ppm/°C
10 K Ω , 0.5%, 5ppm/°C
Precision Voltage Source 320 mV, 1 μ V resolution Analogic 3100, Data Precision
8200 or equivalent
Industrial Terminal and
Interconnect Cable
Programming terminal for Allen-Bradley family processors
ATTENTION
You must calibrate the module in a FLEX I/O system. The module must
communicate with the processor and an industrial terminal. You can
calibrate input channels in any order, or all at once.
IMPORTANT
To allow the internal module temperature to stabilize, apply power to
the module at least 20 minutes before calibration.