Rockwell Automation 900-TC32 Digital Temperature Controllers, Series B User Manual

Page 384

Advertising

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

900-TC32

Open

0 °C/ 32 °F