Rockwell Automation 1756-OF8I ControlLogix Eight-channel Isolated Analog I/O Modules - Manual (Page 39)

Rockwell Automation Publication 1756-UM540A-EN-P - May 2014 39
ControlLogix Isolated Analog I/O Module Features Chapter 2
Module Error over Full Temperature Range
The Module Error Over Full Temperature Range specification represents the
error that occurs if the module’s ambient temperature changes a total of 60 °C
(140 °F), that is, from 0…60 °C (32…140 °F) or 60…0 °C (140…32 °F).
The module accuracy over the full temperature range = 0.1%.
Error Calculated over
Hardware Range A ControlLogix isolated analog I/O module’s calibration accuracy at 25 °C (77
°F) is calculated over the full hardware range of the module and is not dependent
on the application’s use of the range. The error is the same if you are measuring it
across a 10% or 100% portion of a given range.
However, a module’s accuracy at 25 °C (77 °F) is dependent on the hardware
range in which the module operates.
RTD and Thermocouple
Error Calculations When you use the 1756-IRT8I module in temperature mode, error calculations
are achieved by a two-step process.
1. Calculate the module’s error in ohms or volts.
2. Convert the ohm/volt error to temperature for the specific sensor and at
the correct application temperature.
EXAMPLE When the 1756-IRT8I channel uses the Thermocouple (mV) input type, the
input range is -100…100 mV, the module error is 0.2 mV when using 0.1%
of range accuracy.
These error values are the same whether you use 10% or 100% of the
chosen range.