User`s guide

Page 11

Controlinc 1746-C (Version 5.21) Network Master Users Guide (2004-11-18)

3. Network Setup and Connecting to the NIU

In general, the EIM NIU (“Network Interface Unit”) is a “beefed up” and configurable RS232

 RS485

converter.

The ports on the 1746-C, Port1 (PRT1) and

Port 2 (PRT2), are configured for serial

communication using RS-232.

The network communication parameters are

pre-configured and fixed at 9600 baud – 8 bit

– no parity – 1 stop bit.

The NIU isolates and protects the 1746-C

and the PLC from the network and is

primary function is to convert RS232

communications to RS485 communications.

The RS485 connection then communicates

to a ring or ring network.

Note: To help with isolation, there are two

(2) entirely separate boards in the NIU.

However, because of this, there are two (2)

120 VAC connections to the NIU. Ensure

that both are connected (you can jumper the

circuits together).

The Controlinc network is connected to the 1746-C module via the Network Interface Unit (NIU). It

doesn’t matter if you connect:

• Port 2 (PRT2) (bottom DB9 connector): connects to the NIU at the port labeled “HOST A”.

• Port 1 (PRT1) (top DB9 connector): connects to the NIU at the port labeled “HOST B”.

• Port 1 (PRT1) (top DB9 connector): connects to the NIU at the port labeled “HOST A”.

• Port 2 (PRT2) (bottom DB9 connector): connects to the NIU at the port labeled “HOST B”.

However, it is recommended that you remain consistent.

NOTE: You can always connect a PC to the network at the NIU if you …

• Disconnect the cable connecting the 1746-C and NIU.

• Connect the PC using a (serial cable + NULL modem) to the DB9 connector on the NIU.

Figure 1

SLC-500 with

1746-C installed

1746-C