Ardiuno code to Rockwell PLC code TTL serial to RS485

[jbradtke9112]

Hello all,

I am trying to communicate to a brushed DC motor controller through a 1769-ASCII to a RS485/TTL serial adapter. Part numbers for each component are below.

PLC-1769-L30ERM
Communications card-1769-ASCII

RS485-TTL serial Adapter
https://www.droking.com/TTL-To-RS48...utomatic-Flow-Control-Module-Converter-Module

Brush Motor Controller-Basic Micro Solo 30A https://www.basicmicro.com/Roboclaw-Solo-30A-34VDC-Motor-Controller_p_44.html

The motor controller manufacturer provides example code for ardiuno/raspberry Pi/Pyton but I can't figure out how to convert there example to a Rockwell based ladder logic system.

The motor controller is setup for packet serial mode which allows multiple motor controllers on the same RS485 network.

FYI this application is for my family greenhouse business so it's not being installed in an industrial environment.

 

[cardosocea]

Does it have to be Rockwell?
Does it have to be Ladder?

I wouldn't pay too much attention to the Arduino libraries and instead look at the manual and go from there as a lot of constructs from the Arduino won't translate into a PLC, much less a Rockwell one.

One code example that will have a bunch of code for you to reuse is the Modbus that comes with Studio5000. I'd hazard that the CRC calculation is actually the same (although test just to be sure, or if you need, I can test a couple of commands).

The manual isn't clear, but it seems as there is no field delimiter judging by the Arduino library. One thing that I think you need to be aware of will be the endianness of the data as it's not sent in ASCII (as far as I could tell).

 

[jbradtke9112]

Thank you for your response. The PLC is rockwell because this machine has servo motion control on it and thats what I've used in the past so I have a good understanding of Kinetix 5500 Servo drives and Powerflex 525 VFD's.

I spent about 6 hours trying to use the Modbus to DP1 slave sample code provided by Rockwell. No sucess thus far and I have very very limited experience both with the card (1769-ASCII) and RS-485 in general. Do you have an example program of what the PLC should look like?

FYI I know the motor control is setup properly because I hooked an arduino to it last night and was able to control the motor through the example code. Now just need to make it work with the Rockwell PLC.