# Modbus RTU over TCP Timeout Issue

**URL:** <https://forum.inductiveautomation.com/t/modbus-rtu-over-tcp-timeout-issue/25140>\
**Category:** Ignition\
**Tags:** ignition80\
**Created:** [May 20, 2019, 7:29am UTC](https://forum.inductiveautomation.com/t/modbus-rtu-over-tcp-timeout-issue/25140 "2019-05-20T07:29:50Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Kanungoankit](https://avatars.discourse-cdn.com/v4/letter/k/eada6e/32.png) [@Kanungoankit](https://forum.inductiveautomation.com/u/Kanungoankit)\
**Post date:** [May 20, 2019, 7:29am UTC](https://forum.inductiveautomation.com/t/modbus-rtu-over-tcp-timeout-issue/25140/1 "2019-05-20T07:29:50Z")

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Hello ,  
Ignition version 8.0.1 and Ignition 7.9 (Both)

I am first time doing interface of PLC over MODBUS RTU over TCP in ignition . I am using Mitsubishi MT91 card for Modbus communication and verified Modbus communication with MODSCAN32 application . It is working perfectly fine , getting data over Modbus . But when I tired same interfacing with ignition , getting time out error. I increased thresholds also but getting same response . I changed configuration of 125 to 10 as I needed to read only 10 holding register from 400001 to 10 .

| Logger | Time | Message |
| --- | --- | --- |
| TimeoutDaemon | 20May2019 12:55:49 | ScheduledRequest[com.inductiveautomation.xopc.drivers.modbus2.requests.ReadHoldingRegistersRequest@302ed88b] request with key “java.lang.Object@2395d66e” failed due to timeout. |
| ReadHoldingRegistersRequest | 20May2019 12:55:49 | Request failed. FailureType==TIMEOUT |
| TimeoutDaemon | 20May2019 12:55:19 | ScheduledRequest[com.inductiveautomation.xopc.drivers.modbus2.requests.ReadHoldingRegistersRequest@302ed88b] request with key “java.lang.Object@2395d66e” failed due to timeout. |
| ReadHoldingRegistersRequest | 20May2019 12:55:19 | Request failed. FailureType==TIMEOUT |
| ReadHoldingRegistersRequest | 20May2019 12:54:48 | Uncaught Throwable handling response. key=java.lang.Object@2395d66e, req=[], rsp=[01 03 00 00 00] |
| TimeoutDaemon | 20May2019 12:54:48 | ScheduledRequest[com.inductiveautomation.xopc.drivers.modbus2.requests.ReadHoldingRegistersRequest@302ed88b] request with key “java.lang.Object@2395d66e” failed due to timeout. |
| ReadHoldingRegistersRequest | 20May2019 12:54:48 | Request failed. FailureType==TIMEOUT |
| ReadHoldingRegistersRequest | 20May2019 12:54:15 | Request failed. FailureType==DISCONNECTED |
| ReadHoldingRegistersRequest | 20May2019 12:54:15 | Request failed. FailureType==DISCONNECTED |
| TimeoutDaemon | 20May2019 12:54:15 | ScheduledRequest[com.inductiveautomation.xopc.drivers.modbus2.requests.ReadHoldingRegistersRequest@7222a9f7] request with key “java.lang.Object@2395d66e” failed due to timeout. |

Please help me !! thanks in advance !!!

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**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:** [May 20, 2019, 12:15pm UTC](https://forum.inductiveautomation.com/t/modbus-rtu-over-tcp-timeout-issue/25140/2 "2019-05-20T12:15:49Z")

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Maybe you need to set the unit/slave id on your Ignition tags?

It defaults to 0 in Ignition, so try addresses like `[MyDevice]1.HR1` to try unit 1, etc…

If that doesn’t work, a comparison of Ignition and Modscan traffic via Wireshark would help.

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**Author:** ![Kanungoankit](https://avatars.discourse-cdn.com/v4/letter/k/eada6e/32.png) [@Kanungoankit](https://forum.inductiveautomation.com/u/Kanungoankit)\
**Post date:** [May 20, 2019, 2:00pm UTC](https://forum.inductiveautomation.com/t/modbus-rtu-over-tcp-timeout-issue/25140/3 "2019-05-20T14:00:35Z")

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It’s 1 only in my configuration.and i tried both methods of addressing but not happening . Is there any limitations for modbus in ignition trail version ? I hope that’s not the case.

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**Author:** ![Kanungoankit](https://avatars.discourse-cdn.com/v4/letter/k/eada6e/32.png) [@Kanungoankit](https://forum.inductiveautomation.com/u/Kanungoankit)\
**Post date:** [May 20, 2019, 2:04pm UTC](https://forum.inductiveautomation.com/t/modbus-rtu-over-tcp-timeout-issue/25140/4 "2019-05-20T14:04:44Z")

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Can you share basic configuration needed to communicate with modbus to read 10 holding register only. working at you end .

Thanks