ABB RER620 Technical Manual

1MAC309294-MB F Section 12
Relay physical connections
RER620 555
Technical Manual
12.2.4 EIA-485 serial rear connection
The EIA-485 communication module follows the TIA/EIA-485 standard and is intended
to be used in a daisy-chain bus wiring scheme with 2-wire half-duplex or 4-wire
full-duplex, multi-point communication.
12.2.5 Optical ST serial rear connection
Serial communication can be used optionally through an optical connection either in loop
or star topology. The connection idle state is light on or light off.
12.2.6 Communication interfaces and protocols
The communication protocols supported depend on the optional rear communication
module.
The maximum number of devices (nodes) connected to the bus where the
relay is used is 32, and the maximum length of the bus is 1200 meters.

ABB RER620 Specifications

General

Brand	ABB
Model	RER620
Category	Controller
Language	English