User Manual
Rockwell Automation Publication 1756-UM540A-EN-P - May 2014 43
ControlLogix Isolated Analog I/O Module Features Chapter 2
Thermocouple Resolution
Thermocouple resolution indicates the degrees that an application temperature
must change before the 1756-IRT8I module connected to a thermocouple
module reports a change. Resolution depends on the following factors:
• 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
For example, when a 1756-IRT8I module is used with a thermocouple input
type in the following conditions, module resolution is 0.01 °:
• Input channel is connected to a type K thermocouple
• Application temperature is 400 °C (752 °F)
In other words, the application temperature must change by 0.01 ° or
greater for the 1756-IRT8I module used with a thermocouple input to
record a change. If the temperature stays in a range from
399.991…400.009 °C (751.984…752.016 °F), the module continues to
report an application temperature of 400 °C (752 °F).