Troubleshoot incorrect readings on the module, 1756-irt8i module - incorrect temperature readings – Rockwell Automation 1756-OF8I ControlLogix Eight-channel Isolated Analog I/O Modules User Manual
Page 162
162
Rockwell Automation Publication 1756-UM540A-EN-P - May 2014
Chapter 9
Troubleshoot Your Module
Troubleshoot Incorrect
Readings on the Module
Incorrect temperature, current or voltage readings on temperature-sensing and
current/voltage I/O modules are often considered to be the result of a module
needing to be calibrated. This is typically not the case.
ControlLogix isolated analog I/O modules are calibrated before shipment from
the factory and maintain a high degree of module accuracy throughout their
lifespan. Additionally, 1756-IRT8I module channels configured for
Thermocouple inputs perform a resistance self-calibration when the module
power is cycled.
The following sections describe tasks you can use to troubleshoot your module:
•
1756-IRT8I Module - Incorrect Temperature Readings
•
1756-IRT8I Module - Incorrect RTD Readings
•
1756-IF8I Module - Incorrect Input Voltage/Current Readings
•
1756-OF8I Module - Incorrect Output Voltage/Current Readings
1756-IRT8I Module - Incorrect Temperature Readings
To determine the cause of the incorrect reading, first determine the nature of the
incorrect reading. For example, the module can perform as follows:
•
The module always reads maximum.
•
The module always reads minimum.
•
The module reads erratically (data jumping around).
•
The module reads with an offset over the entire range.
First, complete the following tasks.
1.
Check the status indicators to verify that the module is powered and
communicating.
Red or flashing green status indicators indicate a problem. For more
information on the 1756-IRT8I module status indicators,
.