User Manual

Rockwell Automation Publication 1756-UM540A-EN-P - May 2014 41
ControlLogix Isolated Analog I/O Module Features Chapter 2
Thermocouple Error
Thermocouple error at 25 °C (77 °F) indicates the module’s accuracy in
measuring temperature. This accuracy varies depending on these factors:
Input range = -100…100 mV.
Thermocouple sensor type, any of the following:
Type B
Type C
Type D
Type E
Type J
Type K (default value)
Type N
Type R
Type S
Type T
Type TXK/XK (L)
Application temperature, that is, the temperature of the physical location
where the thermocouple is being used.
EXAMPLE
When a 1756-IRT8I module is used with a thermocouple input type in the
following conditions, module error at 25 °C (77 °F) is ±3.74 °:
Connected to a type S thermocouple
Application temperature of 1200 °C (2192 °F)
In other words, the difference between the temperature the module
reports and the actual application temperature can be ±3.74 °.
The module can report an application temperature of 1200 ° C (2192 °F) in
this case when the actual temperature can be in the range from
1196.26…1203.74 °C (2185.268…2198.732 °F).
These calculations used a typical error of 0.02% of full scale range.