Red Lion C48T - Manual (Page 35)

Troubleshooting Serial Communications
If problems are encountered when interfacing the C48T(s) and host device or
printer, the following check list can be used to help find a solution.
1. Check all wiring. Refer to the previous application and use it as a guide to
check your serial communication wiring. Proper polarity of all C48T(s) and
other peripherals must be observed.
2. If the C48T is connected to a “host computer”, device or printer, check to
make sure that the computer or device is configured with the same
communication format as the C48T. The communication format the C48T
will accept is; 1 start bit, 7 or 8 data bits, no parity or 1 parity bit (odd or
even), and 1 stop bit.
3. Check the baud rate and parity in the Programming Menu SErSEt parameter,
and make sure all devices on the line are set to the same baud rate and parity.
4. Check the C48T’s unit address. If the Address command is not used when
transmitting a command to the C48T, the C48T’s address must be set to 0.
See Sending Commands & Data, page 24, for command structure.
5. If two-way communications are to be established between the C48T and a
computer, have the computer receive transmissions from the C48T first.
Activating a User Input, programmed for the print request function, will
initiate transmissions from the C48T.
6. When sending commands to the C48T, an asterisk * (2AH) must terminate
the command.
7. In multiple unit configurations, make sure each unit has a different address
other than zero. If a transmit value or print request command is issued, an
asterisk (*) must be sent before sending another transmission.
8. If all of the above has been done, try reversing the polarity of the transceiver
wires between the C48T (s) and the RS485 interface card. Some cards have
the polarity reversed.
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