Old AB Ethernet Protocol

[The Plc Kid]

What is the name of the old ab ethernet protocol? Like on a 5/05 or som e of the other products.

Will this comm to ethernet ip?

We are looking at buying a controller that is setup for ab ethernet but i thing it uses this old protocol.

[The Plc Kid]

Is it Pcc? How is it different from ehternet ip?

Do they play well?

[kamenges]

The 5/05 does communicate using PCCC. This is the command layer of the DF1 protocol. So basically the 5/05 Ethernet interface is sending DF1 over Ethernet. DF1 is a peer-to-peer only protocol so the 5/05 is limited to the same peer-to-peer communications.

As for your case you need to make sure the device you are getting can communicate using the PCCC protocol. If it is limited to CIP communications the 5/05 will not be able to recognise the communication packets, as far as I know. Also, both the ControlLogix and CompactLogix systems can accept and initiate PCCC read and write sequences using the MSG command.

I hope this helps.

Keith

[The Plc Kid]

This device / controller that i am looking at buying says it works with ab ethernet but has to use a dde connection to configure it's tags

I will be conecting it to a contrologix system where everthing will be ethernet /ip.

I just wanted to know that it would work. So basically i will have to configure a message instruction for this that will comm over ethwernet to this device.

Will the other ethernet /ip traffic effect it? Can it go through the switch with everything else or does it have to be a point to point ethernet connection?

Will it work on the same switch as all the other ethernet / ip devices with no problems?

[kamenges]

If you are using a CLX system you are good to go either way.

Since the device/controller will be using DDE it sounds to me like the CLX will be a passive partner in this exchange. The controller will be doing the reading and writing through a DDE server. So you probably won't need to worry about messaging from the CLX standpoint.

Also, this communication shouldn't mess with any of the CIP stuff you have in place, unless it is going to try and transfer a massive amount of information.

The one wildcard is whether the controller uses tag-based data format or the older PLC/SLC file based format. If it is former you won't need to do anything on the plc side. If it is the latter you will need to set up a little data routing table in the CLX to map the data file requests (N7:2, F8:15, T4:2) into tags in the CLX. This is a accessed under Tools -> Translate PLC5/SLC.

Keith

[Ken Roach]

"A-B Ethernet" usually means the old Allen-Bradley Client-Server Protocol, called CSP or CSPv4.

This protocol implemented the old Programmable Controller Communications Code (PCCC) command set over Ethernet hardware, IP addressing, and TCP transports. PCCC commands had previously been transported by DF1, DH, DHII, DH+, and DH485 networks to various A-B controller families all the way back to the original 1774 PLC.

"A-B Ethernet" is going to be used with SLC or PLC-5 style addressing, for reading and writing data table elements like "N7:10" or "B3:1/5".

ControlLogix uses the modern Rockwell Automation protocol, called the Common Industrial Protocol (CIP) which can be transported by DF1, DH+, ControlNet, DeviceNet, and most importantly the EtherNet/IP transport.

ControlLogix can also use the PCCC command codes to read and write PLC-5 and SLC-500 data tables with addresses like "N7:10", but they do it by transporting the PCCC command code in an EtherNet/IP transport, not a CSPv4 transport. This allows things like session security and multi-hop communication paths.

When ControlLogix talks to ControlLogix, it uses the native ControlLogix objects and commands, and uses the EtherNet/IP protocol exclusively.

SLC-500 and PLC-5E controllers built since about 1999 have a "dual stack" on Ethernet that allows them to simultaneously use the CSPv4 and EtherNet/IP protocols.

No ControlLogix-family controller supports CSPv4. The SLC-5/05 and PLC-5E got forward compatibility instead of the ControlLogix having backward compatibility.

It is vital that you determine if your third-party device uses CSPv4 or EtherNet/IP as the transport protocol if you want it to communicate to a ControlLogix controller.

[The Plc Kid]

ken this is a 3rd party controller it is not a slc or plc 5. The documentations says it has to have its tags setup by its own software that uses a dde link.

So it is not slc or plc 5 addressing types it is tags?

[Ken Roach]

Can you mention the make and model of the controller ?

I recently went through this with a customer with an installed base of Teledenken/SoftPLC controllers that implement a reverse-engineered CSPv4 protocol. These will not communicate directly to ControlLogix; we ended up pursuing a protocol bridge from Fieldserver.

[The Plc Kid]

Ken

It is a blending system from plast control http://www.plastcontrol.net/

I do not have model info yet but they have no downloadable manuals on their site.

As soon as i get it i will post.