# Modbus TCP CC100 Setup

**URL:** <https://www.wago.community/t/modbus-tcp-cc100-setup/2189>\
**Category:** CODESYS\
**Tags:** how-to, cc100\
**Created:** [August 7, 2025, 7:14pm UTC](https://www.wago.community/t/modbus-tcp-cc100-setup/2189 "2025-08-07T19:14:19Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Kychu](https://sea2.discourse-cdn.com/flex016/user_avatar/www.wago.community/kychu/32/1720_2.png) [@Kychu](https://www.wago.community/u/Kychu)\
**Post date:** [August 7, 2025, 7:14pm UTC](https://www.wago.community/t/modbus-tcp-cc100-setup/2189/1 "2025-08-07T19:14:19Z")

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Hello. I’m having trouble configuring Modbus TCP for the CC100 (751-9301) in CODESYS 3.5.

The firewall is disabled.

In QModMaster, I get a “Connection reset” error, but in the Node.js script, it says the port is closed.

P.S. I’m new to CODESYS.

Screenshots below.

 ![image](https://us1.discourse-cdn.com/flex016/uploads/wago/original/2X/4/4bf55ac95b90bb2f3fc4ad8a542f2623ade23965.png)

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<div class="post-metadata">

**Author:** ![AdamReeve](https://sea2.discourse-cdn.com/flex016/user_avatar/www.wago.community/adamreeve/32/59_2.png) [@AdamReeve](https://www.wago.community/u/AdamReeve)\
**Post date:** [August 8, 2025, 2:08pm UTC](https://www.wago.community/t/modbus-tcp-cc100-setup/2189/2 "2025-08-08T14:08:58Z")

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Did you remember to set the IP address of the bridge you want to use in the “Ethernet” device object?

 ![image](https://us1.discourse-cdn.com/flex016/uploads/wago/original/2X/e/e498adfce8ba2b26769b6089dafd6aec81638df6.png)

Are you trying to use the CC100 as the Modbus client or the Modbus server? You have both added to your project and your screenshot shows the client information, but I believe QModMaster only acts as a client as well, not a server.