---
title: "Wiznet WIZ750SR and Modbus"
url: "https://maker.wiznet.io/forum/13608"
markdown_url: "https://maker.wiznet.io/forum/13608/md"
type: "Forum topic"
category: "Serial-to-Ethernet & ConfigTool"
author: "mmaliga"
created: "2019-12-13T01:56:18+09:00"
last_activity: "2019-12-17T12:34:56+09:00"
language: "en"
views: 755
replies: 3
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# Wiznet WIZ750SR and Modbus

## Question

Asked by mmaliga on 2019-12-13 in Serial-to-Ethernet & ConfigTool.

Attempting to use the WIZ750SR (RS485) to communicate to a Modbus device. My other RS485 converters work fine. I can monitor the sent packets, and when I send them with the 750SR, there is no reply.
This is usually due to the character timing. Modbus is very strict. I do not see a way to adjust the character timing and spacing.
Has anybody had success with this device on Mobus over TCP?

## Replies

### Reply 1 by becky, 2019-12-15

What firmware did you use?
Unfortunately, there is no example of implementing Modbus with WIZ750SR.
This link contains code that implements Modbus on the WIZ550S2E module. I hope it helps.

![](https://github.githubassets.com/favicons/favicon.svg) [GitHub](https://github.com/Wiznet/WIZ550S2E-Modbus)

![](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/1/13451e4eb952d3bedb80e8c08f853d257938aa17.png)

### [GitHub - Wiznet/WIZ550S2E-Modbus: Serial to Ethernet Module based on W5500...](https://github.com/Wiznet/WIZ550S2E-Modbus)

Serial to Ethernet Module based on W5500 & Cortex-M0 - GitHub - Wiznet/WIZ550S2E-Modbus: Serial to Ethernet Module based on W5500 & Cortex-M0

### Reply 2 by mmaliga, 2019-12-16 (in reply to reply 1)

Firmware is version 1.2.4

Trying to find applicable notes in link.

Thank you.

Mike

### Reply 3 by mmaliga, 2019-12-17

Seems to be a bit beyond my capabilities.
I’ve used quite a few convertors, but I haven’t done his type of programming before.
I am assuming that this will not download to the 750.

Any hints would be appreciated.

Mike

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Source: https://maker.wiznet.io/forum/13608