Rockwell Automation 1756-XXXX ControlLogix Analog I/O Modules User Manual
Page 12

12
Publication 1756-UM009C-EN-P - December 2010
Table of Contents
Use Ladder Logic To Perform
Run Time Services and
Reconfiguration
Using Message Instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 339
Processing Real-time Control and Module Services. . . . . . . . . . . 339
One Service Performed Per Instruction . . . . . . . . . . . . . . . . . . . . 340
Enter Message Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 344
Configuration Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345
Communication Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347
Unlatch Alarms in the 1756-IF6I Module . . . . . . . . . . . . . . . . . . 348
Unlatch Alarms in the 1756-OF6VI Module . . . . . . . . . . . . . . . . 351
Reconfiguring a 1756-IR6I Module . . . . . . . . . . . . . . . . . . . . . . . 353
Considerations With This Ladder Logic Example . . . . . . . . . . . . 355
Perform Module Reset Service . . . . . . . . . . . . . . . . . . . . . . . . . . . 357
Additional Specification
Information
Analog to Digital (A/D) Converter Accuracy . . . . . . . . . . . . . . . . . . 361
Calibrated Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362
Error Calculated Over Hardware Range . . . . . . . . . . . . . . . . . . . . . . . 363
How Operating Temperature Changes Affect Module Accuracy . . . 363
Gain Drift With Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363
Module Error Over Full Temperature Range . . . . . . . . . . . . . . . 364
RTD and Thermocouple Error Calculations . . . . . . . . . . . . . . . . . . . 365
RTD Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365
Thermocouple Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366
Module Error at 25 °C (77 °F) (-12…30 mV Range) . . . . . . . . . 367
Module Error at 25 °C (77 °F) (-12…78 mV Range) . . . . . . . . . 370
Thermocouple Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373
Module Resolution (-12…30 mV Range) . . . . . . . . . . . . . . . . . . . 374
Module Resolution (-12…78 mV Range) . . . . . . . . . . . . . . . . . . . 377
How to Deal with Incorrect Thermocouple Temp Readings . . . 381