# Struggling with Modbus RTU timing over TCP
**URL:** https://discourse.nodered.org/t/struggling-with-modbus-rtu-timing-over-tcp/101084
**Category:** General
**Tags:** modbus
**Created:** [20 May 2026 07:30 UTC](https://discourse.nodered.org/t/struggling-with-modbus-rtu-timing-over-tcp/101084 "2026-05-20T07:30:45Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Christopher.Scott](https://discourse.nodered.org/u/Christopher.Scott)
#### Post date: [20 May 2026 07:30 UTC](https://discourse.nodered.org/t/struggling-with-modbus-rtu-timing-over-tcp/101084/1 "2026-05-20T07:30:45Z")
I'm trying to integrate a IoT-SS101 with my Node-RED setup. Does anyone have the correct JSON flow for handling the polling interval? Here is the device manual: [https://valtoris.com/wp-content/uploads/2025/11/1CH-RS232-485-422-ETH-V-User-Manual-EN.pdf](https://valtoris.com/wp-content/uploads/2025/11/1CH-RS232-485-422-ETH-V-User-Manual-EN.pdf)
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### Author:  [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [21 May 2026 10:12 UTC](https://discourse.nodered.org/t/struggling-with-modbus-rtu-timing-over-tcp/101084/2 "2026-05-21T10:12:29Z")
Assuming i have the right product page, what you have is a "Serial server, Modbus Gateway, MQTT Gateway" so in theory, you could connect the serial server to 1) the end device (using modbus) and 2) an MQTT broker. That way, you get access to the end device via simple MQTT nodes (core node built in to Node-RED)
Personally, I would have just setup a local RPi (or industrial RPi) and run Node-RED on the edge (near the end device). That is far more flexible.
> [@Christopher.Scott](#):
>
> Does anyone have the correct JSON flow for handling the polling interval?
Polling registers from a Modbus device depends entirely on what you need, how many registers you are reading/writing and how frequently you need them. You first task should be to get a single successful register read/write.
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### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [19 August 2026 10:12 UTC](https://discourse.nodered.org/t/struggling-with-modbus-rtu-timing-over-tcp/101084/3 "2026-08-19T10:12:31Z")
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