RS-485 interface (the MR-0114 submodule) of the CH2 communication interface, characteristics

The RS-485 serial interface submodule (the MR-0114 type, order no. TXN 101 14) is fitted with a complete circuit of bus termination, terminated at C4 (signal BT +) and C3 (signal BT) terminals, see Fig..1. The termination is connected to the bus by connecting BT+ and TxRx+ terminals, or BT- and TxRx- (for an example, see Fig. 2.5.2.1).

Fig. 1 The connection of the RS-485 interface in the MR-0114 submodule and its termination on the C terminal block.

BT+ positive terminal of the bus termination circuit

BT- negative terminal of the bus termination circuit

GND signal ground (a common terminal) interface

TxRx+ positive interface signal terminal RS-485

TxRx- negative interface signal terminal RS-485

Note:

1. The terminals (signals) with identical marking are interconnected inside the submodule.

2. Terminating bus impedance is implemented with the resistance of 150 Ω.

3. All terminals are galvanically isolated from the other circuits in the system.