Mitsubishi Electronics MAM-GM20, MAM-AM6, MAM-GM24, MAM-GM6 Mitsubishi FX at RS485/422, E Attention

Interfaces Mitsubishi FX at RS485/422

RS485 4-wire connection (4-wire bus system, full-duplex)

The terminals of the 2 twisted-pair cables are wired in the same way as for the RS422 connec- tion. Both twisted-pair cables must be terminated if the Mitsubishi Alarm Modem is installed at the start or end of the bus cables. The termination of the receive cables is activated via the DIP switches. The transmit cables must be terminated externally (see figure arrow).

R+	R–	T–	T+	(0V)
				COM2	Slave 1
					R+
					R–
					T–
					T+
Resistor					Slave 2
					R+
					R–
					T–
					T+
					Slave 3
					R+
					R–
					T–
					T+

Fig. 4-9:

The twisted pair cables are to be con- nected according to the opposite sketch. For termination of the sending line, put a resistor (120 Ohm/0,5 W) between the T+ and T- terminals.

E ATTENTION:

Always ensure that the end devices are terminated correctly.

Incorrect or missing termination may give rise to communication faults.

4.5Mitsubishi FX at RS485/422

The Mitsubishi FX is to be connected via the optional RS485-BD or RS422-BD to the optional COM2 of the Mitsubishi Alarm Modem, using 5-wire twisted pair cable. The Alarm Modems DIP switches 3 and 4 must be set to OFF therefore. Perhaps the termination is to be set via DIP switches 3 and 4. More information on these DIP switches are to be found in chapter 4.4 of this manual.

The wiring shall become clear by this depiction:

R+	R–	T–	T+	(0V)
				COM2	Mitsubishi FX

SG	BD
	-
RDA	BD/485-
RDB
SDB	422
SDA

Fig. 4-10:

Connection of the modem at the Mitsubishi FX via the optional RS485/422-BD

Mitsubishi Alarm Modem 4 - 5