# ControlLogix Connection problems **URL:** \ **Category:** Ignition\ **Created:** [February 6, 2019, 6:30pm UTC](https://forum.inductiveautomation.com/t/controllogix-connection-problems/22392 "2019-02-06T18:30:36Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![wschauer](https://avatars.discourse-cdn.com/v4/letter/w/ecccb3/32.png) [@wschauer](https://forum.inductiveautomation.com/u/wschauer)\ **Post date:** [February 6, 2019, 6:30pm UTC](https://forum.inductiveautomation.com/t/controllogix-connection-problems/22392/1 "2019-02-06T18:30:36Z")
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 | ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [February 6, 2019, 6:49pm UTC](https://forum.inductiveautomation.com/t/controllogix-connection-problems/22392/2 "2019-02-06T18:49:50Z")
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? ---
**Author:** ![wschauer](https://avatars.discourse-cdn.com/v4/letter/w/ecccb3/32.png) [@wschauer](https://forum.inductiveautomation.com/u/wschauer)\ **Post date:** [February 6, 2019, 8:10pm UTC](https://forum.inductiveautomation.com/t/controllogix-connection-problems/22392/3 "2019-02-06T20:10:42Z")
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, ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [February 6, 2019, 8:20pm UTC](https://forum.inductiveautomation.com/t/controllogix-connection-problems/22392/4 "2019-02-06T20:20:10Z")
Probably. The driver will reconnect if the status request times out, and that seems to be happening frequently with this particular device.