Micrologix 1400 with Modbus 485 comm cable.

tactical · Mar 4, 2013

Having trouble wiring my device into the 1763-NC01 adapter and can't find any good documentation online. The adapter has connections labeled TERM,A,B,COM,SHLD AND CGND. The device I am wiring has the following wiring guide.

Which wires are wired where? I would assume A and B are for the +data(yellow) and -data(green) wires and the COM is for the Power 0V(Blue) wire? Thanks in advanced.

Ken Roach · Mar 4, 2013

That's the way I would do it, too.

Swapping the Data A and B wires is a standard ritual of RS-485 hookup... no two manufacturers seem to designate them in the same way.

The connection of the SHLD or CGND wires depends on your cable architecture, and the connection of the TERM jumper depends on how many devices are in the system, the cable length, and the presence or absence of a termination resistor at the other end of the cable.

tactical · Mar 4, 2013

Ken Roach said:
That's the way I would do it, too.

Swapping the Data A and B wires is a standard ritual of RS-485 hookup... no two manufacturers seem to designate them in the same way.

The connection of the SHLD or CGND wires depends on your cable architecture, and the connection of the TERM jumper depends on how many devices are in the system, the cable length, and the presence or absence of a termination resistor at the other end of the cable.

Okay thank you for your response. Now if I want to power the device. Do I plug the Power +12V (red wire) into the +DC OUT on the MS 1400 and then take a wire from the -DC OUT and connect it to the COM port on the Modbus 485 adapter?

Ken Roach · Mar 4, 2013

In general, it is best to keep power and communications connections separate.

This device seems to use the "Power 0V" terminal as both the communications and the power common terminal, so you're forced to have both communications and power referenced to the same common terminal.

If you do use the sensor power supply on the MicroLogix 1400, use the +DC and -DC terminals together.

I don't know for sure if the Channel 0 RS-485 COM terminal and the -DC terminal on the MicroLogix 1400 sensor power supply are internally connected or not, but they're definitely not intended to be used interchangeably.

Usually I recommend against using the sensor power supply for anything but sensors: it is very small (I think 250 mA) and shorting or overloading it tends to cause the MicroLogix to fault.

tactical · Mar 4, 2013

Ken Roach said:
In general, it is best to keep power and communications connections separate.

This device seems to use the "Power 0V" terminal as both the communications and the power common terminal, so you're forced to have both communications and power referenced to the same common terminal.

If you do use the sensor power supply on the MicroLogix 1400, use the +DC and -DC terminals together.

I don't know for sure if the Channel 0 RS-485 COM terminal and the -DC terminal on the MicroLogix 1400 sensor power supply are internally connected or not, but they're definitely not intended to be used interchangeably.

Usually I recommend against using the sensor power supply for anything but sensors: it is very small (I think 250 mA) and shorting or overloading it tends to cause the MicroLogix to fault.

The unit I am hooking up requires 80 mA at 12 Volts.

kittydog42 · Mar 5, 2013

I made this document a while ago. I don't bother buying the 1763-NC01, I just mash a standard MiniDIN-8 cable into the port. They go in nicely and stay tight since the guides on the cable housing dig into the molded plastic of the socket. I get the MiniDIN-8 cables as straight through male-male cables from L-COM and cut them in half. I reference the L-COM color codes on this document.

Micrologix 1400 with Modbus 485 comm cable.

tactical

Member

Ken Roach

Lifetime Supporting Member + Moderator

tactical

Member

Ken Roach

Lifetime Supporting Member + Moderator

tactical

Member

kittydog42

Member

Similar Topics