Electro-Voice 1252, 250 operation manual Nexus Meter Port

5.8: RS-485 Connection—Nexus Meter to the Nexus P40N External Display

Insert one end of the supplied RS-485 cable into Port 3 of the Nexus 1250/1252 Meter. Port 3 is factory-set to match the Nexus Display’s baud rate of 9600. To use a port other than Port 3, you must set the port’s baud rate to 9600 using the Communicator EXT software (see the Communicator EXT User Manual). Insert the other end of the cable into the back of the Nexus P40N, P41N or P43N Display. The connectors fit only one way into the ports.

The cable harness brings 17V DC to the displays from the Nexus 1250/1252 Meter, represented by dashed lines in the figure below. RS-485 communication is viable for up to 4000 feet (1219 meters). If your cable length exceeds 200 feet you must use a remote power supply, such as EIG’s PSIO, and:

•Connect the shield to the shield (S) terminal on the Nexus Display port. The (S) terminal on the Nexus is used to reference the Nexus port to the same potential as the source. It is not an earth-ground connection. You must also connect the shield to earth-ground at one point.

•Provide termination resistors at each end, connected to the A(+) and B(-) lines. RT is approximately 120 Ohms. NOTE: Refer to section 5.3 for RT Explanation.

Nexus P40N, P41N or P43N Display Port

Nexus P40N, P41N or P43N Display, Back View

Top

V+

V-

S

B(-)

A(+)

A(+) B(-) S - V +

RT

Bottom

RT

Nexus Meter Port 3 + V - S B(-) A(+)

Figure 5.10: Nexus Meter Connected to Nexus P40N, P41N or P43N External Display

Electro Industries/GaugeTech Doc # E107706 V1.25 5-11