Micrologix 1400 Modbus RTU, RS-485 Communication On Channel 0

I been tasked with setting up communication between a heating cooling unit manufactured by Advantage Engineering and a Microloagix 1400 plc.

The heating cooling unit communicates vis Modbus RTU RS-485 and will be the slave.

This is my first venture into Modbus and could use some guidance.

The threads I have read have provided me with info for the setup in RSLogix 500 on CH0 which i have setup as follows.

Driver - Modbus RTU Master
Buad - 19200 (As per equipment secs)
Parity - None
Stop Bit - 2
Data Bit - 8

I have and old 1761 cable I would like add a sub d9 male connector to and hook up straight to the heating/ cooling unit and the 8 pin end to the PLC to negate the need for the 1763-NC01 cable.

Can someone provide me with the pinout from the 8 pin connector to the 9 pin sub d connector.

The heating cooling unit states that it uses a standard RS-485 port connection.

Thanks

I don't think that the 1763-CBL-PM02 has all the right pins brought out properly to do that. I found these drawings but have not studied them in detail.

https://imgv2-1-f.scribdassets.com/img/document/177220327/original/abd605c8d4/1651760659?v=1

https://plccablehome.files.wordpress.com/2019/04/aefaf-1761-cbl-pm022bpinout.jpg

I like these:
https://www.plccable.com/allen-brad...485-cable-8-pin-mini-din-to-6-pin-micrologix/
Cheaper and better markings that you can see in a dimly lit panel.

+1 for PLCcables.com. Talk to Mark; he knows what he is doing.

The 1400 manual says the combo RS232/RS485 port is the same as the 1100. The 1100 manual (1763-UM001) provides pinouts, but also strong warnings about mixing the 232 and 485 signals. There are also this link, this link, and this link. I am fairly certain that Figure 52 in the 1400 user manual is incorrect (5/A on the DCE device should connect to 8/A(-) on the 1400_.

The trick is figuring out if those pin sketches are looking into the pins' sockets on the jack on the 1400 or at the pins on the cable that goes into the sockets.

I made a working RS232 cable from that first link; see below. Based on that, those images are all looking at the tips of the cable's pins, not the MicroLogix jack pin sockets. Specifically, the distance between pins 3 and 4 is less than the distance between pins 4 and 5.

But again, cf. item (iv) in .sig below, and talk to Mark.

the other option is to put an RS485 to RS232 converter on the server device, but you still need a cable.

drbitboy said:

Talk to Mark; he knows what he is doing.

Click to expand...

Thats a scary thought....

These are my friends when working on this kind of projects, https://www.winford.com/products/cat_brk.php then you can go back and solder once you get it working

Do you have the pinout of the "heating cooling unit manufactured by Advantage Engineering" one companies 'standard' is not the same as others standard or better yet does it have Ethernet?

Thanks to all who replied.

I have contacted the OME of the heating cooling unit for the pinout information but am still unsure of what pins I should be using on the 8 pin RS232/ RS485 Micrologix 1400 port for Channel 0 for RS 485 2 wire communication.

There must be a way to wire to RS 485 directly, I cant imagine the 1763-NC01 cable is doing a whole lot other then establishing a connection to the appropriate pin on the Micrologix 1400 8 pin port.

I will do some more research and post what I find.

Charles4th said:

I cant imagine the 1763-NC01 cable is doing a whole lot other then establishing a connection to the appropriate pin on the Micrologix 1400 8 pin port.

Click to expand...

See the pinout posted... the NC01 does nothing, its just a breakout board so you can hardwire the Mini Din 8

OkiePC said:

https://imgv2-1-f.scribdassets.com/i...1651760659?v=1

Click to expand...