# Issues connecting to Modbus server created through S7

**URL:** https://discourse.nodered.org/t/issues-connecting-to-modbus-server-created-through-s7/32750
**Category:** Industrial
**Created:** [11 September 2020 13:58 UTC](https://discourse.nodered.org/t/issues-connecting-to-modbus-server-created-through-s7/32750 "2020-09-11T13:58:16Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![edwardr](https://avatars.discourse-cdn.com/v4/letter/e/e0b2c6/32.png) [@edwardr](https://discourse.nodered.org/u/edwardr)
#### Post date: [11 September 2020 13:58 UTC](https://discourse.nodered.org/t/issues-connecting-to-modbus-server-created-through-s7/32750/1 "2020-09-11T13:58:16Z")

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I`m getting the error for my modbus server connection on node red -

"Error: {"name":"Port Not Open Error","message":"Port Not Open","errno":"ECONNREFUSED"}"

I`ve matched the connections up for the siemens server on s7 and then also matched the modbus node on Node Red to match but its just not working -

any advice would be much appreciated.

Ed

 ![2](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/f/b/fbd54ac4c49bf13faa945468ac8a41c80ba0d68a.jpeg) ![1](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/7/2/724d708e1b957d2a19d6d160df4ff17fc222bd17.jpeg) ![3](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/1/1/1165941c58a92e77cbfbbb52c225ab99bb3e596f.jpeg)

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### Author: ![machadotiago](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/machadotiago/32/23776_2.png) [@machadotiago](https://discourse.nodered.org/u/machadotiago)
#### Post date: [11 September 2020 15:05 UTC](https://discourse.nodered.org/t/issues-connecting-to-modbus-server-created-through-s7/32750/2 "2020-09-11T15:05:42Z")

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Few things to check

- Can you ping the PLC from the computer where Node-RED is running?
- Is there any output in the ERR output of the Modbus block in the PLC?
- Did you setup the CONNCET input  
 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/a/a/aa439a299d527f65d8a1f08de33b3b5020ec4ac6.png)

and last but no least

- Why using Modbus instead of the S7 node?

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### Author: ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)
#### Post date: [10 November 2020 15:05 UTC](https://discourse.nodered.org/t/issues-connecting-to-modbus-server-created-through-s7/32750/3 "2020-11-10T15:05:43Z")

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