Experimental Physics and
Industrial Control System

"Kasemir, Kay" <[email protected]> · Mon, 16 Jun 2014 14:15:40 +0000

Hello:

Yes, it is interesting to see that other devices are now also accessible via a devicenet-over-ethernet protocol.
At the recent EPICS meeting in Lanzhou, China (http://epics2014.impcas.ac.cn), Suk Choi from RISP, South Korea, reported accessing an LSIS PLC via the EPICS EtherIP driver.
In think in that case the PLC manufacturer tried to be very close to the Allen Bradley implementation, while in your case the device supports the basic CIP Get/Set_Attribute_Single, but of course not the Allen-Bradley-specific commands to read/write tags and to combine multiple reads/writes.

I'm glad that you found my Java implementation of the EtherIP protocol. For network-based devices, Java should be fast enough, so my idea was that this would be good building block. For example, it could be combined with a V4 pvAccess server to create a new way of integrating such devices into an EPICS network. Or if the idea of a Java-based IOC is recovered, that could become its first hardware support.

Thanks,
Kay

On Jun 13, 2014, at 4:07 PM, John Dobbins <[email protected]> wrote:

> We have an Allen-Bradley Power Monitor 3000 which we want to incorporate into our controls. This device supports various protocols including EtherIP which is supported in EPICS as device support for ContolLogix and CompactLogix PLCs. The Power Monitor 3000 however uses EtherIP in a different fashion than the PLCs. The
> Power Monitor is known as an Adapter device in CIP (Common Industrial Protocol which is the basis for EtherIP).  It makes itself available for Implicit and Explicit messaging. 
> 
> CIP  defines various types of Objects. One of these objects is called an Assembly object and is intended to be a generic container for data. The Power Monitor has dozens of Assembly object instances. Each Assembly object has an attribute called 'data' which is a container for an array of numbers, either shorts or floating points. One can read this attribute via Explicit Messaging using the CIP service "Get_Attribute_Single", a service which is already implemented in the EPICS EtherIP support. I found it was straightforward to add support for the CIP service "Set_Attribute_Single" allowing me to control the Power Monitor 3000.
> 
> I know of other devices similar to the Power Monitor 3000. For example, we use an EX250 pneumatic controller from SMC Corp. We originally purchased this device with a modbus/tcp interface but one day someone unintentionally purchased several units on e-bay with an EtherIP interface. At the time we solved the problem by having a ContolLogix PLC read the data from the EX250 and map it into tags. In the case of the EX250 there were only two Assembly objects containing a few words of data. In the case of the Power Monitor 3000 there are dozens of Assembly objects each containing tens of words so I was interested in implementing an approach that by-passed the PLC.
> 
> I am currently working on a stand alone Java application (using Kay Kasemir's Java version of EtherIP) but wanted to share that support for these types of devices is possible.
> 
> John Dobbins
> 
> 

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System