Posted 29 Nov 2021 (edited) I have 0x4c requests from my ipc to the controller, with request path: Class - 0xB2, Instance - 0x004C. And 0x4c responses from the same path, and then "Command Specific Data": example 1 (of the command specific data): 0100a6409d00a6409d00a6409d00a6409d00a6409d00a6409d00a6409d00a6409d00a6409d00a6409d00a6409d00a6409d00a6409d00a6409d00a6409d00 example 2: 0100a7409d00a7409d00a7409d00a7409d00a7409d00a7409d00a7409d00a7409d00a7409d00a7409d00a7409d00a7409d00a7409d00a7409d00a7409d00 example 3: 0100a8409d00a8409d00a8409d00a8409d00a8409d00a8409d00a8409d00a8409d00a8409d00a8409d00a8409d00a8409d00a8409d00a8409d00a8409d00 Looks like it always starts with 0100, then repeating some value. In the first one the repeating value is 00a6409d, and then in the end 00. Or maybe it's 01 and then just repeating values surrounded with 00 or something similar. Is it values surrounded with 00, written using little-endian? Does the variable in request have a name? Edited 29 Nov 2021 by beatopc Share this post Link to post Share on other sites
Posted 29 Nov 2021 This would be a lot easier to look at in wireshark. Can you post a capture file? Share this post Link to post Share on other sites
Posted 30 Nov 2021 Sure, thanks. It contains different examples, but they are pretty much the same. example.pcapng Share this post Link to post Share on other sites
Posted 30 Nov 2021 Hmmm. Not what I expected at all. Rockwell uses Service 0x4c differently on each class I've dealt with, and class 0xb2 is not one of them. For example, on class 0x6c, that service reads a template definition (UDT or module-defined types). In that form, it takes 6 bytes of additional payload in the request and delivers a complicated but documented reply. (Rockwell's Logic Data Access manual, publicly available.) What model processor is this? 1 person likes this Share this post Link to post Share on other sites
Posted 30 Nov 2021 I found a reference that hints that class 0xb2 manages (?) the processor's trend objects. 1 person likes this Share this post Link to post Share on other sites
Posted 30 Nov 2021 This is compact logix 5380. I'm not sure what trend objects are exactly, but I'll try to check. Is there a documentation that tells how to read that data so I know I interpret it correctly? Thanks! Share this post Link to post Share on other sites
Posted 30 Nov 2021 No documentation. Private Rockwell object. Trends are data logging elements within a Logix processor that can run at PLC speed, then deliver the results to slower devices. 1 person likes this Share this post Link to post Share on other sites
Posted 30 Nov 2021 This is how we use it. Thanks for the help! Share this post Link to post Share on other sites