# Can't connect to s7-300

**URL:** <https://forum.inductiveautomation.com/t/cant-connect-to-s7-300/73865>\
**Category:** Ignition\
**Created:** [May 17, 2023, 9:12pm UTC](https://forum.inductiveautomation.com/t/cant-connect-to-s7-300/73865 "2023-05-17T21:12:27Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![lachguerabdallah](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/lachguerabdallah/32/25558_2.png) [@lachguerabdallah](https://forum.inductiveautomation.com/u/lachguerabdallah)\
**Post date:** [May 17, 2023, 9:12pm UTC](https://forum.inductiveautomation.com/t/cant-connect-to-s7-300/73865/1 "2023-05-17T21:12:27Z")

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hello,  
I'm having problems connecting a PLC, it is a siemens s7-300. I have to connect 3 PLCs, I have been able to connect one without problems, the other two do not work.

the three plc are in the same network. and they are configured in the same way. only one works with Ignition.

the rack and slot number is correct, port 102 is open and I have disabled the firewall.

Has anyone experienced something similar? What do I have to look at in the PLCs configuration? I am using STEP7.

thank you

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/d/8/d809680edaa766b3495f7ea2e0cb23fd17effb57.png)

the logs:

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/b/6/b69fa421c80610619e9a56375b1e070736f9e862.png)

````auto
java.net.SocketException: Connection reset

at java.base/java.net.SocketInputStream.read(Unknown Source)

at java.base/java.net.SocketInputStream.read(Unknown Source)

at java.base/java.net.SocketInputStream.read(Unknown Source)

at com.inductiveautomation.iosession.socket.AsyncSocketIOSession.run(AsyncSocketIOSession.java:71)

at java.base/java.lang.Thread.run(Unknown Source)```
````

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<div class="post-metadata">

**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [May 17, 2023, 9:21pm UTC](https://forum.inductiveautomation.com/t/cant-connect-to-s7-300/73865/2 "2023-05-17T21:21:26Z")

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> [@lachguerabdallah](#):
>
> `java.net.SocketException: Connection reset`

That is the target device saying "I'm too busy" or "I'm not configured to do this". IIRC, you must explicitly configure (in the PLC) the number of get/put connections that will be allowed. If other systems are also connecting, someone will be refused.

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<div class="post-metadata">

**Author:** ![lachguerabdallah](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/lachguerabdallah/32/25558_2.png) [@lachguerabdallah](https://forum.inductiveautomation.com/u/lachguerabdallah)\
**Post date:** [May 19, 2023, 9:30am UTC](https://forum.inductiveautomation.com/t/cant-connect-to-s7-300/73865/3 "2023-05-19T09:30:13Z")

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Thanks, I tried connecting the plcs with Kepserver and it gives me the same problem, with that I rule out that it is something related to the Ignition driver.

I am going to check the communications configuration in the PLCs.

thanks again.

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<div class="post-metadata">

**Author:** ![Kfoldesi](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kfoldesi/32/11327_2.png) [@Kfoldesi](https://forum.inductiveautomation.com/u/Kfoldesi)\
**Post date:** [May 19, 2023, 7:24pm UTC](https://forum.inductiveautomation.com/t/cant-connect-to-s7-300/73865/4 "2023-05-19T19:24:11Z")

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TIA or Step7?  
I know in TIA the OPC has to be turned on - there are 2 ways of doing it as well. Also, it pesters you if you don't set up security - if everything is not set just right it defaults to 'I'm not working".....

Good luck 🙂