ROC364 Instruction Manual
3-18
Input and Output Modules
Rev Jun/05
NOTE:
The RTD module input can be calibrated before installing it in the field when short wire
runs will be used, but if the RTD module is used as a temperature input to a flow calculation,
then the RTD should be calibrated at the same time as the pressure inputs.
A4464821
1
AB
C
DECADE BOX
RTD
WH
T
C
WH
T
RED
B
A
Figure 3-21. Calibration Setup
Table 3-1. Calibration Resistance Values
ALPHA
–50ºC (58ºF)
100ºC (212ºF)
0.00385
80.31 Ohms
138.50 Ohms
0.00392
79.96 Ohms
139.16 Ohms
NOTE:
Resistance values for RTD probes with other alpha
values can be found in the temperature-to-resistance
conversion table for that probe.
1.
Connect the decade box as shown in Figure 3-21.
2.
Set the decade box to the –50
°
C (–58
°
F) resistance value corresponding to the RTD alpha value
in Table 3-1.
3.
Enter the value displayed for “Raw A/D Input” as the value for “Adjusted A/D 0%” using the
Analog Inputs configuration screen for the RTD input. Refer to ROCLINK > Configure > I/O >
AI Points Advanced tab.
4.
Set the decade box to the 100
°
C (212
°
F) resistance value given in Table 3-1.
5.
Enter the value displayed for “Raw A/D Input” as the value for “Adjusted A/D 100%” using the
Analog Inputs Advanced configuration screen for the RTD input.
6.
Enter –50
°
C (–58
°
F) for “Low Reading EU” using the Analog Inputs configuration screen. Refer
to ROCLINK > Configure > I/O > AI Points General tab.
7.
Enter 100
°
C (212
°
F) for the “High Reading EU” using the Analog Inputs configuration screen.
8.
Click Apply to save the changes.
