Reading Ethernet IP from a CLX from a Non-CLX

Hello All,

I'm trying to read data from a CompactLogix controller with a WAGO 750-881. I am able to read from other Ethernet/IP devices but I've been unsuccessful reading from the CLX.

I created several array tags in the CLX, ie. DeleteMeSINT[10], DeleteMeINT[10], DeleteMeDINT[10] and I'm attempting to read them with the following message attributes:
GET_ATTRIBUTE
Class = 4
Instance = 3 (SINT), 4 (INT), or 5 (DINT)
Attribute = 3 (Data attribute)

See the attached file for the error message.

I'd appreciate it if someone would point me in the direction of an A-B manual which contains the Class/Instance/Attributes for the CLX.

Thanks

(8{)} .)
(Yosi)

The only messaging integration documents that I am aware of for ControlLogix are here:

http://www.rockwellautomation.com/enabled/guides.html

To my knowledge, the ControlLogix doesn't have a generic, un-named Assembly object you can connect to as though it was an I/O module.

Produced Tags might use the Assembly object, but you have to name the tag as the connection point during the establishment of an implicit I/O connection.

Because they're so simplified in RSLogix 5000 I've never had the need to examine the Produced/Consumed Tag connection process from the perspective of anything except Logix 5000 controllers.

It seems to me that the way to do it is the other way around; define a generic Assembly object in the Wago controller, and treat it as a Generic I/O Module in the I/O tree of the ControlLogix.

http://www.wago.com/wagoweb/documentation/app_note/a2032/a203200e.pdf

If I was going to dig into this deeply, I would sniff the traffic of an Produced/Consumed Tag connection between two Logix family controllers, then compare it to the traffic from the Wago 750-881 to see if they're even using the same approach.

Hi Ken,

I'm planning on using standard messaging between the two. I appreciate your input and will look up the document you referenced. Either way I'll post my findings.

Thanks!

(8{)} .)
(Yosi)

As I understand it, and I could be horribly wrong, using Ethernet/IP in CIP, you need send/receive. Thus you need the MSG block in the CLX.
As I understand, you're trying to read data, which means unsolicited messages, meaning PCCC commands for read/write.

Which method does the WAGO support?

Ethernet/IP Redux

The WAGO is a CoDeSys controller so I'm using the EML library. I've attached the description information for the instruction that I'm using in addition to the different services it can perform. I don't see Read or Write services. When I use the WAGO with a generic Ethernet/IP device I've only had to provide the Class, Instance, Attribute, and Member.

In this case I want to read a tag. From what I've learned so far this basically means that I can leave the above out and just provide a tag name. That's great but I still need to know what service to use.

Thanks!

(8{)} .)
(Yosi)

Look for this document on the WAGO site.
I believe this is what you're after.
a203200e.pdf
This is an application note.
"Accessing Ethernet IP Network Variables in a Wago 750-841 with a ControlLogic PLC".

Wrong direction

Thanks bkottaras

I'm familiar with this note. It describes how to set up the WAGO for access by the CLX. I want the WAGO to be the master.

I can read from Ethernet/IP devices that support the Class/Instance etc... services but the CLX doesn't. I don't even know if this can be done with the EML library!

With that said (I don't know if you noticed this) I can leave out things like Class etc. without getting a fault from the instruction. I just get that same annoying message that there is no such data in the destination controller. Perhaps I should provide IP and Tagname only.

I'll keep plugging away.

Thanks!

(8{)} .)
(Yosi)

I reversed engineered some of the Native Tag addressing in the past to get data from a CLX device since it does not support getting tag data through a typical Class/Inst/Attr mechanism. Here are my notes decoding the message bytes to read/write two different arrays. The service codes I needed are listed, not sure if this format is supported by the Wago device. I think the service codes are vendor specific so if there is a standard list to choose from it may not be possible to get this data. On my system, I was able to send arbitrary CIP messages so I could implement these codes / paths.

Thanks Robert,

I really appreciate this. The most obvious thing I missed was the full path ie. IP + backplane + CPU location. That's got to be a minimum. I hope to check that out next week. I'm not sure that the instruction supports anything other than the listed services but I'm checking up on that too. If worse comes to worse I'll have the CLX write to the WAGO. That's a no-brainer.

Thanks again,

(8{)} .)
(Yosi)

It's working.

Just wanted to let you know that it's finally working. The biggest issue wasn't the encoding but the fact that I'm running on VMWare player. I had to shut down my wireless in order to get it to work.

Thanks for all of your help.

(8{)} .)
(Yosi)

I have the same issue with VMWare player on my laptop. If the wireless is on, it appears to try to use THAT to connect instead of the NIC card. There's probably a setting that will fix it, but I haven't had time to research it.



-Eric

Eric Nelson said:

I have the same issue with VMWare player on my laptop. If the wireless is on, it appears to try to use THAT to connect instead of the NIC card. There's probably a setting that will fix it, but I haven't had time to research it.



-Eric

Click to expand...

Hi Eric,

There is a setting in VMWare Manager. I haven't found it in the Player. You have no idea how much hair I pulled out until I figured that out...

Well, now we know.

Thanks,

Yosi

Yosi - What was your final configuration?

WAGO 750-88x running the FB I developed talking to a CLX 1756-ENET.

Hope that helps.

(8{)} .)
(Yosi)

Thanks Yosi - Actually what I was wondering about was your final comm block configuration....class, instance, attribute, etc.