Ethernet/IP General Status Code

[Corsair]

In some communications with a Micro 820 I'm seeing a General Status Code of hex CC decimal 204. My CIP spec is pretty old and it lists that range as 'Future Extensions'. Anybody know what the value corresponds to? Is it something that is AB specific?

Thanks.

 

[Mark-]

The specific command generating the error response might help. Do you have a Wireshark capture of the exchange?

 

[Ken Roach]

Please explain in more detail what "some communications" constitutes.

Are you writing a comms driver ? Messaging from a ControlLogix ? Using a UDFB in the Micro 800 to send data to another device ?

The *extended* error code 16#0204 generally means a connection timeout in ControlLogix so it's recognizable in that context.

But you're seeing that value in decimal and maybe as a primary error code, so that's... dunno what it is.

 

[Corsair]

It's C code that is reading attributes of an Identity object with Get Attribute Single. It seems to be intermittent. I'll wireshark it to see what it says.

 

[AlfredoQuintero]

The current version of the CIP spec still lists the 0x2F -0xCF range of general statuses as "Reserved by CIP for future extensions". Is this EtherNet/IP adapter a product registered, meaning that has passed the ODVA conformance test suite?

 

[Ken Roach]

Interesting ! While I wouldn't be shocked if the Micro 800 had a firmware bug or two, the Identity Object is one of the simplest CIP objects and Get Attribute Single is one of the simplest CIP services.

Do you get the same behavior with a List Identity command ?

Are you reading only the required attributes of the Identity object, or also some optional ones ?

I agree that when you're doing development work and getting intermittently different responses, Step 1 is to use a packet capture tool like Wireshark to be sure that you're sending the same requests.

 

[Corsair]

My stupid on this one

I wrote the packet parser and then I didn't follow my own rules on how to use it. It was a parsing problem. The Micro 820 is performing as it should.

Big thanks to all for the excellent assistance.

I'm working on the second generation of the general EIP explorer that is embedded in my interface. It's a challenge to write something that finds as much as possible and yet does it with usable speeds. If anybody is interested in writing something like that for themselves they can PM me and I'll share what I've learned so far about an exploration strategy.

I'm not a big AB PLC fan but I do love the protocol. Schneider invented Modbus and then sat on their rears and did nothing with protocols for (literally) 50 years. AB worked out something that you can really do some great things with. I'm working with a customer to embed it in some DSP firmware and the more I learn about CIP the more I find I can do with it. It's got a tough learning curve but that goes with the capabilities.

Now I get to break the news to the customer that I need a new CIP spec...

 

[AlfredoQuintero]

Now I get to break the news to the customer that I need a new CIP spec...

Great that you found the problem. I fully agree with you that CIP is a great specification. ODVA is doing a huge effort drafting and maintaining this specification. I hope your customer will see the value of buying it. ODVA pays its staff's salaries through the revenue of selling the specification and conformance testing.