Powerware FCC 15 manual Four-Wire Networks, RS-485 Terminal Strip

WIRING THE MODBUS CARD

Four-Wire Networks

The Modbus Card also supports four-wire, half-duplex, RS-485 networks.

Figure 7 shows a detailed view of four-wire connections using the

Modbus Card terminal strip.

Master Device

T--

R--

T+

R+

Gnd

Slave Device #1

Gnd R+ T+ R-- T--

RT *

Slave Device #2

Gnd R+ T+ R-- T--

UPS with
Modbus Card	TxD+ RxD+ TxD– RxD–

RT *

RT *

RT *

*See Note

Figure 7. Four-Wire RS-485 Modbus Network

NOTE Belden 9842 or equivalent cabling (a dual twisted-pair shielded cable with ground) is recommended.

NOTE If the Modbus Card is the last device installed in the network chain or the length of the network cable is excessive, termination needs to be enabled (see page 10).

RS-485 Terminal Strip

The RS-485 five-position terminal strip provides an alternate interface to attach the RS-485 transmission lines. This connector also allows external resistors to be applied to terminate the network.

Before connecting the RS-485 network to the Modbus Card, remove the detachable plug from the 5-pin terminal strip connector. The RS-485 signal names are shown just above the connector (see Figure 8).

For two-wire networks. Connect the RS-485 network signal TxD(+) to the

RxD(+) input signal on the Modbus Card terminal strip. Connect the

RS-485 network signal TxD(–) to the RxD(–) input signal on the Modbus

Card terminal strip. The Modbus Card factory-default jumper setting for

J9 and J10 is two-wire communication.

8 EATON Powerware® Modbus® Card User’s Guide S 164201376 Rev C www.powerware.com