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MANUAL P/N 316005 REV: B
Figure 6-2 RS-232 Module, Top View
(Controller Cover Removed)
6.5 RS-232 Troubleshooting
Because the RS-232 "standard" is found in a bewildering array of configurations, the first thing to do if trouble
arises is check the following configuration options:
1.
Check the switch settings.
Be sure baud rate, character format and framing, and interface protocol are matched to your host
computer or terminal's requirements. Note that there can be several mismatched parameters.
Check to see if your computer requires the reversed-polarity RTS convention.
2.
Check the interface wiring.
The pin designations for the RS-232 connector are shown in Figure 6-2. Note that the "received"
and "transmitted" data lines are defined as seen by the 316. Many companies supply "null modems"
or switch boxes for the purpose of reconfiguring the control lines for particular applications.
3.
Check the command format.
Be sure the strings you output to the 316 are in accord with the syntax defined in Section 6.3.
6.5.1 RS-232 Troubleshooting Guide
Symptom
Possible Cause
µP Failure LED is illuminated or flashing
Microcontroller failure
No response or garbled output
Baud rate incorrect, character length incorrect,
or stop bit(s) incorrect
OVERRUN ERROR message
Stop bit(s) incorrect or host software failure
PARITY ERROR message
Parity incorrect or electrical noise on the
transmission line
SYNTAX ERROR message
Message to the 316 is not in accord with the
specified syntax or failure to assert DCD
handshake line
