Specifications

Use of Analytical Module Hardware Test Box, continued

The following procedure should be used to test the electrical

characteristics of the TCD beads. Refer back to figure 4-12.

Electrical Test

Bead Select

Switch Setting

Expected

Resistance at 25°C

1-8 27-33 kΩ

9 > 2 MΩ

Table 4-2: Module Hardware Tester

Step Procedure

1. With the external test meter connected as previously

described, set the BEAD SELECT switch to position 1.

2. Read the measurement on the meter. Verify that the value is

within the range shown in table 4-2.

3. Repeat for 2-8 (for double module) or 2-5 (for single

module).

Note: If an out of range reading is found, then the selected bead is

suspected faulty. Replace the bead pair using the procedure

described in the Analytical Module section of this chapter.

Note that positions 1-2 and 5-6 relate to the bottom bead

pair on the respective post and positions 3-4 and 7-8 relate

to the top bead pair on the respective post.

4. Set external test meter to its highest range and then set

BEAD SELECT switch to position 9. Verify that an open

circuit is measured (greater than 2 MΩ).

Note: A value less than 2 MΩ found on position 9 indicates that

there is a short between the metal hardware of the module

and the TCD beads. This could be due to a faulty wiring

harness or some other fault. Troubleshoot as needed.

5. After electrical test, the external meter can be disconnected.

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