ControlLogix Message (Block Transfer) Error

Hi all!

This is my first thread here (yay). I'll try to contribute to the Automation community as much as I can and I hope this forum can help me explaining the CLP fails for my Manager hahaha.

Here's the deal.. I got a ControlLogix using 1756-DHRIO to communicate with SLC500 remote racks. There was an 1746-NO4I card on one of the remotes which had nothing higher than 4mA on it's output... and in the MSG (Block Transfer) of that Output card there was an error (Error Code: 16#00CC Unknown error). Since the network and CPU and everything else was allright, we rebooted the DHRIO network (unplugged the network from the main DHRIO card) and then finaly the MSG error was gone and it started working back as usual.

Notes: Theres no schedule for the MSG routine.. it simply runs every scan like a regular routine... theres around 15 MSG routines in this CLP. I know this isnt the best but it has been working like this since the beginning of the project (6 years ago).

The only thing possible I see here is that happened a real quick network failure on the DH+ and when it recovered the MSG routine couldn't syncronize again due to it's lack of schedule.

Please someone help me on this theory

Also... I can't find anywhere what is Error Code 16#00CC

Farnesi,

I would not favour running 15 messages "unscheduled", and would either set up some timed triggers for them, or move the MSG code into a Periodic Task.

Check the RTS (Real-Time Sample) rate for your 1746-NO4I card and any other Analog I/O you have. There is no point exchanging data values any faster than the I/O modules RTS rate, you are simply wasting network bandwidth.

Are all the 15 MSG's going to the same I/O adaptor ?

Have you added any new, or changed the sizes of any existing communications on the RIO recently ?

Have you changed any of the CLP code ?

What is you CLP task execution time ?

Also, you probably already have the answer to the 16#00CC error, it is "unknown".

Are all the 15 MSG's going to the same I/O adaptor ?
They are all 1756-DHRIO Channel B but different racks.

Have you added any new, or changed the sizes of any existing communications on the RIO recently ?
No.

Have you changed any of the CLP code ?
Yes, 3 weeks ago. I added some integration software.

What is you CLP task execution time ?
Around 220ms.