# Modbus Device Timeouts

**URL:** <https://forum.inductiveautomation.com/t/modbus-device-timeouts/96803>\
**Category:** Ignition\
**Created:** [October 4, 2024, 1:03am UTC](https://forum.inductiveautomation.com/t/modbus-device-timeouts/96803 "2024-10-04T01:03:25Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![jacob.ramirez](https://avatars.discourse-cdn.com/v4/letter/j/9dc877/32.png) [@jacob.ramirez](https://forum.inductiveautomation.com/u/jacob.ramirez)\
**Post date:** [October 4, 2024, 1:03am UTC](https://forum.inductiveautomation.com/t/modbus-device-timeouts/96803/1 "2024-10-04T01:03:25Z")

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Modbus pro's out there, why would a certain device cause Modbus comms timeouts when connected?

I have 2 devices on a RS485 network and one of them tends to cause timeouts when connected. When it's removed the other device doesn't have any timeouts at all.

We've tested this out with the problem device with other Modbus devices and found the same behavior.

What could be causing the problem?

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**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [October 4, 2024, 1:56am UTC](https://forum.inductiveautomation.com/t/modbus-device-timeouts/96803/2 "2024-10-04T01:56:23Z")

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A flawed transceiver on that device could be flipping some bits, causing CRCs to reject packets. Perfectly reasonable. Replace that device.

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**Author:** ![jacob.ramirez](https://avatars.discourse-cdn.com/v4/letter/j/9dc877/32.png) [@jacob.ramirez](https://forum.inductiveautomation.com/u/jacob.ramirez)\
**Post date:** [October 4, 2024, 2:11am UTC](https://forum.inductiveautomation.com/t/modbus-device-timeouts/96803/3 "2024-10-04T02:11:42Z")

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It happens all the time with that particular brand, it's a flow meter. Just something with the Modbus on that brand of flow meter tends to cause issues with our other Modbus devices.

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**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [October 4, 2024, 12:25pm UTC](https://forum.inductiveautomation.com/t/modbus-device-timeouts/96803/4 "2024-10-04T12:25:27Z")

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Put a scope on it. That brand might not be conforming well to the expected voltage waveforms.