Watlow Series 922 - Manual (Page 71)

Appendix
71
WATLOW Series 922 User's Manual
Thermocouple Field Calibration Procedure
Equipment Required
• Type "J", "K", or "T" (depending on model number) Reference
Compensator with reference junction at 0
°
C/32
°
F AND
• Precision Millivolt Source.
OR
• Type "J", "K", or "T" thermocouple calibrator.
• 4-1/2 digit Digital Voltmeter (DVM). Can be used with either configuration
above.
Setup and Calibration
k
NOTE:
Before calibration on an installed control, make sure all data and
parameters are documented.
1. Connect the input side of the thermocouple reference compensator to #6
Positive and #8 Negative for Channel 1 [#3 Positive and #5 Negative for
Channel 2] on the Series 922 terminal strip. Short the output side of the
compensator and turn on the compensator. See Figure 38.
If a t/c calibrator is used, connect to terminal #6 positive and #8 negative
for Channel 1 (#3 positive and #5 negative for Channel 2) in the 922
terminal strip. Set the calibrator for the appropriate thermocouple.
Also, set either 0
°
C or 32
°
F.
2. Connect AC line voltage, L1 to #17, L2 to #20, ground to #21. Jumper for
correct line voltage. See Chapter 4 "How to Install and Wire".
3. Set DIP Switch #6 to ON. Apply power to the unit and allow it to warm up
for 15 minutes. The unit should be in the TEST mode.
4. Connect DVM common to TP2 and DVM positive to TP1 on the A007-1728
circuit board, located on the top side behind the center chassis support.
DVM should be set up for DC volts, and in a range capable of displaying
6.3000 volts.
T/C Calibration
Figure 38 -
Reference Compen-
sator-to-Series 922
Connection Diagram
Series 922
Terminal Strip
Channel 1
Output
(-)
(+)
Input
Open
Test
On
Copper Wires
+1
-3
T/C Wires
(-)
(+)
6
8
6
8
7
Series 922
Terminal Strip
Channel 2
6
8
3
5
4
Omega Model
MCJ-J or
MCJ-K or
MCJ-T