# I ran into a tricky problem when using node-red-contrib-s7 to connect to a PLC

**URL:** https://discourse.nodered.org/t/i-ran-into-a-tricky-problem-when-using-node-red-contrib-s7-to-connect-to-a-plc/90299
**Category:** General
**Created:** [21 August 2024 00:50 UTC](https://discourse.nodered.org/t/i-ran-into-a-tricky-problem-when-using-node-red-contrib-s7-to-connect-to-a-plc/90299 "2024-08-21T00:50:19Z")
**Posts on this page:** 5
**Page:** 1

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### Author: ![Xiang](https://avatars.discourse-cdn.com/v4/letter/x/9fc348/32.png) [@Xiang](https://discourse.nodered.org/u/Xiang)
#### Post date: [21 August 2024 00:50 UTC](https://discourse.nodered.org/t/i-ran-into-a-tricky-problem-when-using-node-red-contrib-s7-to-connect-to-a-plc/90299/1 "2024-08-21T00:50:19Z")

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A PLC can have its data read when no password is set, but if a password is configured, the data cannot be read. However, I haven't been able to find where to input the password to establish a connection.

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### Author: ![KarolisL](https://avatars.discourse-cdn.com/v4/letter/k/a4c791/32.png) [@KarolisL](https://discourse.nodered.org/u/KarolisL)
#### Post date: [21 August 2024 05:37 UTC](https://discourse.nodered.org/t/i-ran-into-a-tricky-problem-when-using-node-red-contrib-s7-to-connect-to-a-plc/90299/2 "2024-08-21T05:37:19Z")

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Can you share addresses that you are trying to read?

S7 node doesn't require password to read PLC.  
What password are you talking about?

This is my project password setup:

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/9/6/96f79f3255ea00353a45a7cb59e16b0dbba751e1.png)

and I can read PLC data without any issues

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### Author: ![Xiang](https://avatars.discourse-cdn.com/v4/letter/x/9fc348/32.png) [@Xiang](https://discourse.nodered.org/u/Xiang)
#### Post date: [21 August 2024 05:49 UTC](https://discourse.nodered.org/t/i-ran-into-a-tricky-problem-when-using-node-red-contrib-s7-to-connect-to-a-plc/90299/3 "2024-08-21T05:49:09Z")

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With this password in place, the connection can be established, but data reading fails and errors occur. The errors stop when I remove the password, and everything works normally then.

 ![99d11c77a1da64b682e4c9c79d612b2](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/8/5/85d9cf52b90f006fe22d0a0736335fdaec1dfff1.jpeg)

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### Author: ![KarolisL](https://avatars.discourse-cdn.com/v4/letter/k/a4c791/32.png) [@KarolisL](https://discourse.nodered.org/u/KarolisL)
#### Post date: [21 August 2024 06:13 UTC](https://discourse.nodered.org/t/i-ran-into-a-tricky-problem-when-using-node-red-contrib-s7-to-connect-to-a-plc/90299/4 "2024-08-21T06:13:08Z")

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> [@Xiang](#):
>
> With this password in place

Which password? TIA has so many places to enter passwords.

Also please check: [https://support.industry.siemens.com/forum/WW/en/posts/connecting-to-hmi-error-code-0x8104/270924](https://support.industry.siemens.com/forum/WW/en/posts/connecting-to-hmi-error-code-0x8104/270924)

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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: [19 November 2024 06:13 UTC](https://discourse.nodered.org/t/i-ran-into-a-tricky-problem-when-using-node-red-contrib-s7-to-connect-to-a-plc/90299/5 "2024-11-19T06:13:21Z")

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