Western Telematic PollCat III, Руководство по обслуживанию

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9.1.1. Diagnosis of Local Access Problems
Caution:
This procedure must be performed while the unit is
powered ON, and therefore, should only be
performed by a qualified technician. Take proper
precautions to avoid injury by electric shock.
1. Remove the Top Cover from the PollCat III.
2. Refer to Figure 2.3 and find the IC at board location U26.
This is the RS-232 interface component for the Computer
Port. Use an oscilloscope to check the IC at location U26.
While transmitting commands to the PollCat III, the pins
should register as follows:
a)
Communication Signals to PollCat III:
i. Pin 6 (Data Input): ~+12 to ~-12 VDC
(see Figure 9.1).
ii. Pin 11 (Data Output): +5 VDC.
b) Communication Signals to Computer:
i. Pin 7 (Command Response Output):
While Active: ~+12 to ~-12 VDC (See Figure 9.1)
While Inactive: ~-12 VDC
ii. Pin 10 (Command Response Input): +5 VDC
If any of the signals are missing or incorrect, the IC at
location U26 should be replaced as described in
Section 9.1.2. The WTI part number for this IC is XB-099.
In most cases, replacement of this component will resolve
communication problems with the Computer Port.
9-2
PollCat III Service Guide
Figure 9.1: Data Signal Levels