Rockwell Automation 900-TC32 Digital Temperature Controllers, Series B - Manual (Page 384)

Publication 900-UM007D-EN-E -January 2011
C-6 Calibration
• Set the cold junction compensator designed for compensation of
internal thermocouples to 0
°C. However, make sure that internal
thermocouples are disabled (tips are open).
• In the above figure, STV refers to a standard DC current/voltage
source.
• Use the compensating conductor designed for the selected
thermocouple. However, note that when thermocouples R, S, E, B, W
or PLII, or a non-contact temperature sensor is used, the cold junction
compensator and the compensating conductor can be substituted with
the cold junction compensator and the compensating conductor for
thermocouple Type K.
• Connecting the Cold Junction Compensator — Correct process values
cannot be obtained if you touch the contact ends of the compensating
conductor during calibration of a thermocouple. Accordingly,
short-circuit (enable) or open (disable) the tip of the thermocouple
inside the cold junction compensator as shown in the figure below to
create a contact or non-contact state for the cold junction compensator.
Figure C.5 — Connecting the Cold Junction Compensator
This example describes how to calibrate the Bulletin 900 Controller when a
thermocouple input is currently selected.
1. Connect the power supply.
2. Connect a standard DC current/voltage source (STV), precision digital
multimeter (DMM), and contact junction compensator (e.g., zero
controller as in the figure below) to the thermocouple input terminals
(refer to Figure C.6 below).
Enable
Cold Junction Compensator
Compensating Conductor
900-TC8
900-TC16
or
900-TC32
Open 0 °C/ 32 °F
900-TC8
900-TC16
or
900-TC32
Cold Junction Compensator
Compensating Conductor
Short-Circuit
0 °C/ 32 °F
Disable