Fluke 2620A Open Thermocouple Response Test, Decade Resistance Box, Hydra Input Module, J K N E T

Maintenance 6

Performance Tests

4-WIRE (4T) CONNECTION

	11	12		13	14	15	16	17	18	19	20
SOURCE
	H L		H L	H L	H L	H L	H L	H L	H L	H L	H L
(4-WIRE)
SENSE
	H L		H L	H L	H L	H L	H L	H L	H L	H L	H L
(4-WIRE)
	1	2		3	4	5	6	7	8	9	10

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

J

K

N

E

T

Thermocouple Accuracy Specifications 1 Year

@ 18-28 Degrees C

±0.40°C

±0.44°C

±0.53°C

±0.38°C

±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.

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