Cabling help on Using 1761-CBL-PM02 as RS485 Modbus on 1100

harryting

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So, I need a RS485 Modbus slave to do some testing.

Well, since I don't have any RS485 Modbus Slave sitting around but does have a Micrologix 1100, I went ahead and attempted to make it work.

Also, since I don't have a 1763-NC01 cable, which looks to me like a standard breakout, I'm using a 1761-CBL-PM02 mini-din to DB9 cable. Here's where I ran into some confusion. The RS485 2-wire should go on pin 4 and 5 of the NC01 which corrospond to pin 1 and 8 on the mini-Din. However, looking at the pinout for the PM02, pin 1 and 8 shows as 24V and GND, which makes no sense. Maybe it's only 24V/GND if it's configured as a RS232 instead of RS485?
 
The older MicroLogix controllers (1000,1200,1500) had +24V on Pin 1 and DC Common on Pin 8 so that they could power accessory devices like the Net-AIC, Net-DNI, and Net-ENI or the Hand-Held Programmer with a DIN8<->DIN8 cable.

In order to not damage a personal computer's RS-232 port, the 1761-CBL-PM02 cable does not connect to Pin 1.

By the way; that diagram posted in 2007 by Ron Doran was either a prank or just weirdly wrong. Knowing him, probably he just failed to check it.

The modern MicroLogix controllers (1100, 1400) jettisoned that +24V accessory power feature in favor of a non-isolated RS485 data port on Pins 1 and 8 (with data common on Pin 2), but you need either a custom cable or the 1763-NC01 breakout cable to access those pins.
 
Thanks everyone, now I'm back to the drawing board. Oh, sharp eyes, the diagram looks very similar to the other PM02 diagram I seen but now I see it's "off".

Also, I had the thought to get some mini-8-pins cable or connectors to "roll my own" only to see that the AB mini 8-pin connector is different than the "standard" 8-pin mini-DIN. <facepalm> I guess I'll have to dig through the recycle bins in the plants to see what I can find.
 
I logged into our Tech Connect account and that is where my references came from. I do have a PDF print of 823750, but no clue as how to post a PDF.

The NC01's are simple to use with Modbus and ML1100, ML1400. Also quite cheap.
 
I go dig through the bins at Re-PC for old Apple serial cables; those are 8-pin Mini-DIN with a similar locking collars.
 
My thing is that an NC01 is only around 40 bucks. How much is your time worth?

Had a customer ask us if we could build an Automation Direct cable they can get for 30 bucks. Sure, but it might cost you 10x the price. Told our guy fielding this just to buy it and mark it up.
 
There are free modbus slaves out there but modbus poll and modbus slaves are good softwares. You would just need a 232 -485 converter to hook up your pc.
 
My thing is that an NC01 is only around 40 bucks. How much is your time worth?

Had a customer ask us if we could build an Automation Direct cable they can get for 30 bucks. Sure, but it might cost you 10x the price. Told our guy fielding this just to buy it and mark it up.
No disagreement there.

We have internal customer only and I would rather not talk about organization structure unless I'm lubed up with lots of beer and wine.

This project is 1/2 serious and 1/2 hobby.
 

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