Calibrating Thermocouples - Omron E5AK PROGRAMMABLE TYPE User Manual

CHAPTER 7 CALIBRATION

7.2 Calibrating Thermocouples

F Preparations
Connecting the
Cold Junction
Compensator
7--4
• Calibrate according to the type of thermocouple, thermocouple 1
group (K1, J1, L1, E, N, W, PLII) and thermocouple 2 group (K2, K2,
L2, R, S, B, T, U).
• When calibrating, do not cover the bottom of the controller. Also, do
not touch the input terminals (Nos.11 and 12) or compensating con-
ductor on the E5AK-T controller.
100-240VAC
(24VAC/DC)
10
SOURCE
9
8
7
6
5
4
3
2
1
DMM
• Set the cold junction compensator designed for compensation of inter-
nal thermocouples to 0_C. However, make sure that internal thermo-
couples are disabled (tips are open).
• In the above figure, STV refers to a standard DC current/voltage
source, and DMM refers to a precision digital multimeter.
However, note that DMM is required only when the transfer output
function is supported.
• Use the compensating conductor on the selected thermocouple. How-
ever, note that when thermocouple R, S, E, B, W and PLII is used, the
cold junction compensator and the compensating conductor can be
substituted with the cold junction compensator and the compensating
conductor for thermocouple K.
Correct process values cannot be obtained if you touch the contact ends of the
compensating conductor during calibration of a thermocouple. Accordingly, short
(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.
Cold junction
compensator
0°C/32°F
E5AK
Compensating conductor
30 20
31 32
29 19
28 18
27 17
26 16
25 15
24 14
23 13
22 12
33
21 11
Compensating
conductor
Short
E5AK
Compensating conductor
STV
Cold junction
compensator
0_C/32_F
Cold junction
compensator
0°C/32°F
Open