Rockwell Automation 1790P-T4T0 CompactBlock LDX I/O Thermocouple Modules - Manual (Page 42)

Publication 1790-UM003A-EN-P
3-12 Module Data, Status, and Channel Configuration for DeviceNet
Determining Module
Update Time The module update time is defined as the time required for the module to
sample and convert the input signals. Module update time is dependent
on the number of input channels and the input filter selection.
The fastest update time occurs with the 500Hz filter enabled. The
following table shows update times for all filter frequencies.
Calculating Accuracy Overall accuracy is determined from the combination of the module and
the thermocouple. The total error is the sum of the following:
• module accuracy and error due to temperature
• thermocouple error
• error due to thermocouple lead wire
• CJC error
Module and Temperature Error
The combined module error and error due to ambient temperature is
shown in the table below.
Table 3.8 Module Update Time
Filter
Frequency Module Update Time
10 Hz 3.0 seconds
25 Hz 1.3 seconds
50 Hz 668 milliseconds
60 Hz 580 milliseconds
100 Hz 383 milliseconds
250 Hz 204 milliseconds
500 Hz 144 milliseconds
Table 3.9 Module and Temperature Error
Thermocouple Type Error (10Hz Filter) 0 to 55°C
B ±4.2°C
E ±2.5°C
J ±2.8°C
K ±3.3°C
R ±3.6°C
S ±3.6°C
T ±1.3°C
N ±3.1°C