ControlLogix Connection problems

Ignition
1

We have an Allen Bradley ControlLogix 1756-L1, running version 12.27 that is having a persistent communication issue. We are able to connect to the PLC and it works fine for 20-30 minutes then seems to time out and reset. It drops out communication for a few minutes then works again.
We have no issues connecting to other similar and older plc’s but for some reason this one is causing trouble.
All ideas welcome.
running latest version of ignition as well.

ABControlLogixTransportPool 06Feb2019 12:41:10 [Tower_A] Reseting CIP connection for transaction ID of 1452
ABControlLogixTransportPool 06Feb2019 12:41:10 [Tower_A] Reseting CIP connection for transaction ID of 1451
TimeoutDaemon 06Feb2019 12:41:10 [ABControlLogixProcessorStatusRequest] request with key “1451” failed due to timeout.
ControlLogixDriver 06Feb2019 12:41:10 Comm state changed to INACTIVE
ControlLogixDriver 06Feb2019 12:35:25 [Tower_A] Updating tagManager with edit version 39939 with 1818 tags
ControlLogixDriver 06Feb2019 12:35:25 [Tower_A] Browse complete.
ABControlLogixBrowseRequest 06Feb2019 12:35:25 [Tower_A] Browse complete.
ABControlLogixBrowseRequest 06Feb2019 12:35:25 [Tower_A] Creating browse nodes.
ABControlLogixBrowseRequest 06Feb2019 12:29:18 [Tower_A] Creating browse request using HIGH priority.
ControlLogixDriver 06Feb2019 12:29:18 Comm state changed to ACTIVE
ControlLogixDriver 06Feb2019 12:29:16 Processor info: Vendor=1, Product Type=14, Product Code=3, Revision=12.29, Product Name=1756-L1/A 1756-M1/A ARG_12_64
ABControlLogixTransportPool 06Feb2019 12:29:12 [Tower_A] Reseting CIP connection for transaction ID of 1329
ControlLogixDriver 06Feb2019 12:29:12 Comm state changed to INACTIVE
TimeoutDaemon 06Feb2019 12:29:12 [ABControlLogixProcessorStatusRequest] request with key “1329” failed due to timeout.
ABControlLogixReadRequest 06Feb2019 12:29:12 Read Request failed due to TIMEOUT. First item: Global.TLACoreAvg, Transaction: 1328
ABControlLogixTransportPool 06Feb2019 12:29:12 [Tower_A] Reseting CIP connection for transaction ID of 1328
TimeoutDaemon 06Feb2019 12:29:12 ScheduledRequest[[ABControlLogixReadRequest]] request with key “1328” failed due to timeout.
ControlLogixDriver 06Feb2019 12:25:19 [Tower_A] Updating tagManager with edit version 39939 with 1818 tags
ControlLogixDriver 06Feb2019 12:25:19 [Tower_A] Browse complete.
ABControlLogixBrowseRequest 06Feb2019 12:25:19 [Tower_A] Browse complete.
ABControlLogixBrowseRequest 06Feb2019 12:25:19 [Tower_A] Creating browse nodes.
ABControlLogixBrowseRequest 06Feb2019 12:19:15 [Tower_A] Creating browse request using HIGH priority.
ControlLogixDriver 06Feb2019 12:19:15 Comm state changed to ACTIVE
2

I don’t know if any of these questions apply to firmware this old, but:

  1. is there any way to check the comms / cpu load on the PLC?
  2. can you increase the overhead time slice?
  3. are there other devices or systems talking to this PLC?
3

Hi Kevin,
I will look into how best to monitor the CPU load. I have been using the ignition gateway factor as a first glance at processor/com load. Sitting currently at 15-25%
The Overhead time slice is set at 25% and with the older processors i am not sure if increasing this will allot more time to the comms but i will give it a shot.
We do have a few HMI interfaces. PanelView and RSView32 also communicating with the PLC.

From the sound of it though, this looks like its coming back to a overload of either the comms or CPU? and not a setting in Ignition?
Thanks again,

4

Probably. The driver will reconnect if the status request times out, and that seems to be happening frequently with this particular device.