RE: Options for reviving old Allen Bradley PLC implementations

[Bryce Karnaghan <Bryce.Karnaghan@synchrotron.org.au>]

Another  option could be to use Prosoft modbus module “MVI46-MNET” and the rich EPICS modbus support from Mark Rivers and others.

 

One issue I have found with Prosoft modules is that as it is a completely standalone processor it is possible that the PLC could be stopped and the Prosoft module will continue to communicate stale values up to the IOC. I would be implementing heartbeats (in both directions) in the PLC logic.

 

Bryce Karnaghan  

 

 

From: tech-talk-bounces@aps.anl.gov [mailto:tech-talk-bounces@aps.anl.gov] On Behalf Of Chestnut, Ronald P.
Sent: Saturday, 6 November 2010 6:31 AM
To: tech-talk@aps.anl.gov
Subject: Options for reviving old Allen Bradley PLC implementations

 

We have a number of old Allen Bradley PLC implementations here at SLAC. One of these uses a Data Communication Card (DCM) in VME is connected to the SLC5 SLC500s. One path we are considering is using an RSLogix PLC (which has good EPICS support) as the master PLC, and slaving the SLC5 PLC to that. It turns out that there exists a package to translate the ladder logic from SLC500 to RSLogix.

 

Another group here is asking the following:

 

“We have some old SLC 5/04 PLCs from Allen Bradley that we wanted to make EPICS compatible. I found a third party SLC module that talks Ether/IP:

http://www.prosoft-technology.com/prosoft/products/for_rockwell_automation/platform/slc/mvi46_dfnt

 

Will this module work to provide the EPICS support? “

 

Another piece of information is from Ernest Williams: He warned us against the direct SLC-50x EPICS driver support, since it uses its own protocol (DFI?) and has a poor reputation and poor support.

 

So the questions to the community are

 

How are you reviving old PLC support? What has or has not worked? What do you recommend?

 

 

Ron Chestnut

 

 

 

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