Red Lion LEGEND - Manual (Page 50)

SERIAL CONNECTIONS
When wiring, remove the 10-position terminal block, which is on the top
board at the rear of the unit. Refer to the top label and configure the
RS485/RS232 jumpers for the desired interface. Then, refer to the numbers
listed on the label with the terminal description for installing each wire in its
proper location.
For RS485 the data (transceiver) wires connect to the A (+)/TXD and B
(-)/RXD terminals. It is recommended that shielded (screened) cable be used
for serial communications. This unit meets the EMC specifications using
Alpha #2404 cable or equivalent. There are higher grades of shielded cable,
such as, four conductor twisted pair, that offer an even higher degree of noise
immunity. 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. The signal
ground is connected from only one Legend Plus to the equipment. If
necessary, the shield can be used as the signal ground.
TERMINAL DESCRIPTIONS
COMM. - Common required for some applications.
A (+)/TXD & B (-)/RXD - The Legend Plus transmits and receives on these
two terminals which are connected to the external device.
TX EN. - Used primarily with a Red Lion Controls (RLC) GCM422 module to
interface with an RLC model DMPC printer or connect to a Legend Plus in
a 20 mA communication loop with other units.
For connection to an GCM232 Converter Module, refer to diagram below.
For connection to an RS232 port on a computer, refer to diagrams below.
When all connections are made, replace the terminal block into its proper
location.
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