1756-L82 and serial connection

We are trying to replace a PLC5 at a remote site with ControlLogix. The site connects with a modem. We verified we could connect to the SCADA software over the modem using an L61 processor. However it looks like we are getting an L82, and looking at the manual it doesn't look like DF1 is supported. Is there another option for talking over a modem?

Prosoft and others make serial port modules for controllogix.

Is the connection purely for SCADA purposes, or do you need to try to do editing and monitoring of the control program through this connection ?

I agree that the MVI56-DFCM module from Prosoft is probably the most straightforward way to allow a ControlLogix to respond to PLC-5 style data table reads and writes from a SCADA system. You'll have to do some re-work of the data table logic to move that data into and out of the MVI56 module, but since you're doing a platform conversion that's not a huge addition to the scope of the project.

Make sure you're certain about the addressing details of all the data table registers being read and written on that PLC-5 and what DF1 function codes are being used. You might have to re-arrange some stuff so that it's well packed into INT and REAL data tables.


Another very easy-to-use device is the Real-Time Automation gateways. The 460ETCDFM might do the trick. Check with them to see if it can function as a DF1 Server that maps to ControlLogix array tags.

It’s just for Scada control. Thanks for the leads. I’m still pretty new to ControlLogix, so this will definitely be a learning experience for me.

If you already have a functional data link via modem to an L61 then there is definitely merit with sticking to that approach. If you must upgrade processors I would highly recommend setting up a VPN over the modem connection and adjusting the SCADA DA/UA server connections to work over that. You can certainly supply data via the Prosoft cards previously mentioned as well. I feel like a VPN over the modem will give you more options in the future if/when the data connection is changed/upgraded. I’m somewhat spoiled in this regard though so will always lean this direction.

This processors are no cheap!! to easy yourself, why don't you get what is need instead of L82.

I presume the modem uses DF1-R232 comm layer, if not use EtherNet from the L82 processor to connect to the modem if it has an EhterNet option.

In Automation too many converters, especially when dealing with data brings more problems, and nothing is "plug & play". Hope this helps