Red Lion LEGEND User Manual
Page 38
SERIAL CONNECTIONS
When wiring, remove the 10 position terminal block, which is the top
board at the rear of the unit. Refer to the numbers listed on the top label with
the terminal description for installing each wire in its proper location.
The two data (transceiver) wires connect to the TX/RX (+) and TX/RX ( )
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 RS485 transceiver lines. The signal
ground is connected from only one Legend to the RS485 equipment. If
necessary the shield can be used as the signal ground.
When all connections are made, replace the terminal block into its proper
location.
TERMINAL DESCRIPTIONS
COMM. - Common required for some applications.
TX/RX (+) & TX/RX (-) - The Legend transmits and receives on these two
terminals which are connected to the external device.
TX EN. - Used primarily in a 20 mA communication loop with other units.
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