Open thermocouple response test – Fluke 2625A User Manual
Page 141
Maintenance
Performance Tests
6
6-13
12
11
13 14 15 16 17 18 19 20
2
1
3
4
5
6
7
8
9
10
SOURCE
(4-WIRE)
SENSE
(4-WIRE)
H L
H L
H L
H L
H L
H L
H L
H L
H L
H L
H L
H L
H L
H L
H L
H L
H L
H L
H L
H L
4-WIRE (4T) CONNECTION
DECADE
RESISTANCE
BOX
HYDRA
INPUT
MODULE
oo20f.eps
Figure 6-3. 4-Terminal Connections to Decade Resistance Box
Table 6-4. Performance Tests for Thermocouple Temperature Function (IPTS-68/ITS-90)
Thermocouple Type
Thermocouple Accuracy Specifications 1 Year
@ 18-28 Degrees C
J
±
0.40
°
C
K
±
0.44
°
C
N
±
0.53
°
C
E
±
0.38
°
C
T
±
0.45
°
C
Open Thermocouple Response Test
1.
Switch OFF power to the instrument and disconnect all high voltage inputs.
2.
Remove the Input Module from the rear of the instrument. Open the Input Module
and connect test leads to the H (high) and L (low) terminals of channel 1. Install the
Input Module back into the instrument.
3.
Reconnect power and switch the instrument ON.
4.
Connect the test leads from the Input Module to an 820 ohm resistor.
5.
Select the temperature and K-type thermocouple function for channel 1. Press MON.
6.
The value displayed should approximate the ambient temperature.
7.
Replace the 820 ohm resistor with a 4 kilohm resistor to simulate a high resistance or
open thermocouple.
8.
Verify a reading of "otc".
9.
The Open Thermocouple Response Test is complete. However if you desire to
perform this test on any other Input Module channel (2 through 20) repeat steps 1
through 8 substituting in the appropriate channel number.