red lion C48C, Instruction Manual

Page: 39 / 56

Serial Connections
When wiring, refer to the numbers listed on the label with the terminal
description for installing each wire in its proper location.
For RS-485, the data (transceiver) wires connect to the A(+) and B(-)
terminals. It is recommended that shielded (screened) cable be used for serial
communications. In some applications, a signal ground may be required to
establish a ground reference. The signal ground is required if the equipment does
not have internal bias resistors connected to the transceiver lines. If necessary,
the shield can be used as the signal ground.
TERMINAL DESCRIPTIONS
COMM. - Common required for communication hook-up.
A (+) & B (-) - The C48C transmits and receives on these two terminals which
are connected to the external device.
Troubleshooting Serial Communications
If problems are encountered when interfacing the C48C(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 example and use it as a
guide to check your serial communication wiring. Proper polarity of all
C48C(s) and other peripherals must be observed.
2. If the C48C 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 C48C. The communication format the C48C
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

parameter,
and make sure all devices on the line are set to the same baud rate and parity.
4. Check the C48C’s unit address (

). If the Address command is not used
when transmitting a command to the C48C, the C48C’s address must be set
to 0. See Sending Commands & Data, page 26, for command structure.
5. If two-way communications are to be established between the C48C and a
computer, have the computer receive transmissions from the C48C first.
Activating a User Input, programmed for the print request function, will
initiate transmissions from the C48C.
6. When sending commands to the C48C, an asterisk * (2AH) must terminate
the command. Make sure a carriage return or line feed does not follow the
command terminator.
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 C48C(s) and the RS485 interface card. Some cards have
the polarity reversed.
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