ML1000 MSG Instruction

[brewer 0]

I have a SCADA system communication over serial radios and to one of my site I am getting a Error Message in my MSG Instruction "Hex 37" MSG timeout in local Processor".  The odd thing is i have communication with this site.  I am only running one message at a time and cascading through the messages.  Some of the messages do get through. My message time out is set to 5 and am having this issue with three messages to the same PLC.  So it is slowing my system down.

[Ken Roach 194]

What is your master controller ?  

When you say "some of the messages do get through", do you mean that of the three to that site two of them always get through, or some of each of the three sometimes get through ?    Does your system do any statistical collection on error rates or counts ?

Have any changes been made to the system lately ?   Do your radios have any independent diagnostics ?

In general, Error code 0x37 really does mean "timeout";   the local controller sent a query to the remote controller, and never got a reply.

This is different from the sort of error that you would get if the data table was unavailable, or there was a corrupted value like a CRC error.   With a MicroLogix 1000, the data tables are fixed in size and type, so the risk of mis-addressing is mostly limited to typos at the master side.

 

[brewer 0]

The master controller is a ML1100 Series B.  The controller it is having trouble communicating to a Compct Logix L5332E .  I am not doing error tracking yet but I would guess I am getting 1 out of every 3 successfully.  All the other controllers are communicating with are ML1100.   I just seems odd that I am getting messages through  so my config should be ok.  

I have dropped the time out from 5 to 1 in the MSG instruction and my poll is better but that's just because the timeouts are finishing sooner.  I am only reading 20 registers per instructions.

[Ken Roach 194]

OK, that's a different set of conditions and devices.

Is your communications over serial, or over TCP/IP ?

What revision of firmware is the CompactLogix 1769-L32E running ? 

What protocol are you using;  DF1 full duplex, or half-duplex, or half-duplex Radio-Modem ?

Telemetry can be hard to troubleshoot, and the tools and techniques aren't as commonplace as ordinary automation electronics.  I used to make my living hooking up protocol analyzers and hunting for the correlation between communication failures and weather/temperature/vibration/traffic/time.

[brewer 0]

Serial Communications

L32E REv 20.19

DF1 Radio Modem

 

 

 

[brewer 0]

L32 Serial.bmp

L32 System Protocol.bmp

[brewer 0]

I have attached Screen Shots of the Communication Set-up

ML Channel 0.bmp