Different Communication Protocols

[Prayder]

I realize that when using PLCs there are a myriad of different communication protocols used from Modbus TCP, Ethernet/IP, CIP, DeviceNet, DF-1, etc... my question is how would you know which one you are actually using and if your using something like a controllogix processor, is there a way to manually choose which type of communication protocol to use or is it always set by default?

 

[jstolaruk]

It will be device dependent and sometimes requires additional hardware. As an example, ControlNet, DeviceNet or Profibus requires additional modules added to act as scanners (or adapters).
Depending on the model, Controllogix/Compactlogix PLCs will natively support Ethernet/IP and/or DF1. Some of controllers don't have built-in ethernet ports and require an additional module in the rack to provide the ports. Again, its highly model dependent.

 

[DwSoFt]

And modbus requires a Prosoft in rack card

 

[V0N_hydro]

I used a $500 digi one IAP for talking to modbus devices from control/compact logix and it worked flawlessly. I think there were 5 PLCs talking to 5 different modbus slaves, maybe they all talked to the same one too. highly recommend.

 

[automationtechie]

You can use a Gateway to convert from 1 protocol to another. In most cases, your software or master will be able to communicate via Modbus since it is pretty standard in our industry.

http://www.icpdas-usa.com/converters_and_gateways.html

 

[Firejo]

And modbus requires a Prosoft in rack card

Actually the MicroLogix 1100 and 1400 along with SLC5/03, 04 and 05’s will all do Modbus RTU. The SLC’s might need a firmware upgrade but it is doable. There is also a communications module for a CompactLogix that will provide Modbus RTU communications.

 

[geniusintraining]

When it comes to Allen Bradley... this is a good read for PCCC and Ethernet/IP

https://www.rockwellautomation.com/...s-partners/technology-licensing/eipexp1_2.pdf

I find it interesting to see what's going on behind what we normally see, I am making a few trainers for a college that is going to be teaching this... guess a upper level programming ? way back... when I first started, I spoke with a guy that worked for Wonderware and was writing code for the software, I thought about getting into that line of work