# ClickPLC C201CPU, ignition slow to read changes to modbus tags, 0.74s delay to

**URL:** <https://forum.inductiveautomation.com/t/clickplc-c201cpu-ignition-slow-to-read-changes-to-modbus-tags-0-74s-delay-to/109657>\
**Category:** Maker\
**Created:** [August 12, 2025, 6:23pm UTC](https://forum.inductiveautomation.com/t/clickplc-c201cpu-ignition-slow-to-read-changes-to-modbus-tags-0-74s-delay-to/109657 "2025-08-12T18:23:29Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![a.belz](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@a.belz](https://forum.inductiveautomation.com/u/a.belz)\
**Post date:** [August 12, 2025, 6:23pm UTC](https://forum.inductiveautomation.com/t/clickplc-c201cpu-ignition-slow-to-read-changes-to-modbus-tags-0-74s-delay-to/109657/1 "2025-08-12T18:23:29Z")

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Why are my modbus tcp tags so slow to register a change in ignition? Is there anyway to decrease the lag time"? I am using a ClickPLC C2-01CPU with one QMR7-0N-OF photoelectric sensor wired in NPN as a proximity switch. My PLC code is very simple, just one line. I have the tags labeled in ignition designer based on the documentation for how to set up a MODBUS TCP tag.

> **[Modbus Addressing | Ignition User Manual](https://www.docs.inductiveautomation.com/docs/8.1/ignition-modules/opc-ua/opc-ua-drivers/modbus/modbus-addressing)**
>
> Manually Addressing a Modbus Device

I have an input Prox set up as DI1 and an output Output\_1 set up as C1. My stopwatch measurement of the time between tripping the sensor and ignition registering is about 0.74s. I am on localhost and hardwired directly to the plc over ethernet.

 ![Prox](https://us1.discourse-cdn.com/inductiveautomation/original/3X/6/8/68ae4326010129ac0d3af739da6d05644ccd5e6b.png)

 ![Output 1](https://us1.discourse-cdn.com/inductiveautomation/original/3X/8/3/836ca78c9712e69e082e16e183d0f0726b98c06c.png)

 ![Click PLC Rungs](https://us1.discourse-cdn.com/inductiveautomation/original/3X/0/a/0a87a879d99523840002ae5569ed356599f676b5.png)

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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:** [August 12, 2025, 6:45pm UTC](https://forum.inductiveautomation.com/t/clickplc-c201cpu-ignition-slow-to-read-changes-to-modbus-tags-0-74s-delay-to/109657/2 "2025-08-12T18:45:32Z")

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