Cpu; Communication; General Rs-232 Troubleshooting - Teledyne 100E Instruction Manual

Model 100E Instruction Manual

11.5.9. CPU

There are two major types of CPU board failures, a complete failure and a failure
associated with the Disk-On-Chip (DOC). If either of these failures occur, contact the
factory.
• For complete failures, assuming that the power supplies are operating properly
and the wiring is intact, the CPU is faulty if on power-on:
o The watchdog LED on the motherboard is not flashing
o There is no activity from the primary RS-232 port (COM1) on the rear panel
even if "? <ret>" is pressed. Note that the RS-232 port has programmable
baud rates from 200 to 115200 baud. Since the CPU board remembers the
programmed baud rate even when power is off, this means that there is no
default baud rate for the port when the instrument boots up, the rate will be
whatever it was last programmed to be. In some cases, configuration
memory might be corrupted, and the baud rate could be a random
unrelated value. For these reasons, it is best to test all possible baud rates
when performing this test. See the RS-2323 Communication section below,
for more details regarding port configuration.
In some rare circumstances, this failure may be caused by a bad IC on the motherboard,
specifically U57, the large, 44 pin device on the lower right hand side of the board. If this
is true, removing U57 from its socket will allow the instrument to start up but the
measurements will be invalid.
• If the analyzer stops during initialization (the vacuum fluorescent display shows
some text), it is likely that the DOC, the firmware or the configuration and data
files have been corrupted.
11.5.10. RS-232 Communication

11.5.10.1. General RS-232 Troubleshooting

T-API analyzers use the RS-232 protocol as the standard, serial communications
protocol. RS-232 is a versatile standard, which has been used for many years but, at
times, is difficult to configure. T-API conforms to the standard pin assignments in the
implementation of RS-232. Problems with RS-232 connections usually center around 4
general areas:
• Incorrect cabling and connectors. This is the most common problem. See Table 6-
16 for connector and pin-out information and Section 6.9.3.
• The communications (baud) rate and protocol parameters are incorrectly
configured. See Section 6.9.4. on how to set the baud rate.
• The COM port communications mode is set incorrectly (Section 6.9.6).
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