# uSwitch CS Modbus TCP Weirdness

**URL:** <https://forum.inductiveautomation.com/t/uswitch-cs-modbus-tcp-weirdness/115892>\
**Category:** Ignition\
**Tags:** modbus\
**Created:** [June 8, 2026, 2:45pm UTC](https://forum.inductiveautomation.com/t/uswitch-cs-modbus-tcp-weirdness/115892 "2026-06-08T14:45:00Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![dion.botha](https://avatars.discourse-cdn.com/v4/letter/d/46a35a/32.png) [@dion.botha](https://forum.inductiveautomation.com/u/dion.botha)\
**Post date:** [June 8, 2026, 2:45pm UTC](https://forum.inductiveautomation.com/t/uswitch-cs-modbus-tcp-weirdness/115892/1 "2026-06-08T14:45:00Z")

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Hello,

I have this device connected to Ignition using the Modbus TCP driver with all default settings. Among other things, it has 2 general purpose input points and 2 relay outputs. If I try to address, the first relay with C1, it works - I can toggle it in the tag browser (though not reliably...). If I then try to address the second relay with C2, it does not work but if I delete the first relay tag then the second relay tag starts to work. Anyone experienced something like this? I had similar issues with a different device a few months ago (Monigear MN-WTHM) and was able to get it to work only by using address mapping rather than addressing in the tag browser. I have tried both for the uSwitch CS but nothing I do is quite making things work fully.

[WiFI/Ethernet Web Controlled Relays and I/O uSwitch CS](https://uhavecontrol.com/collections/the-uswitch-product-line/products/uswitch-cs)

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<div class="post-metadata">

**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:** [June 8, 2026, 2:51pm UTC](https://forum.inductiveautomation.com/t/uswitch-cs-modbus-tcp-weirdness/115892/2 "2026-06-08T14:51:18Z")

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![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/a/9/a964da37e97fc2f01dcfe1e66e7a1f7f8f6f7075.png)

The way this is written makes it seem plausible that the device only lets you read one coil/input/register at a time, despite the function codes being for multiple.

You can try some of these advanced settings on the driver: [Connecting to Modbus Device | Ignition User Manual](https://docs.inductiveautomation.com/docs/8.3/ignition-modules/opc-ua/opc-ua-drivers/modbus/connecting-to-modbus-device#read-request)

Not sure if they will help or not.

edit: or, if those don't work, try setting the max per register/coil/etc to 1: [Connecting to Modbus Device | Ignition User Manual](https://docs.inductiveautomation.com/docs/8.3/ignition-modules/opc-ua/opc-ua-drivers/modbus/connecting-to-modbus-device#read-request)