# Error while trying to connect PLC to EtherNet/IP

**URL:** <https://forum.universal-robots.com/t/error-while-trying-to-connect-plc-to-ethernet-ip/19205>\
**Category:** Robot Communication\
**Created:** [February 11, 2022, 12:58pm UTC](https://forum.universal-robots.com/t/error-while-trying-to-connect-plc-to-ethernet-ip/19205 "2022-02-11T12:58:09Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![anon63378011](https://avatars.discourse-cdn.com/v4/letter/a/7ea924/32.png) [@anon63378011](https://forum.universal-robots.com/u/anon63378011)\
**Post date:** [February 11, 2022, 12:58pm UTC](https://forum.universal-robots.com/t/error-while-trying-to-connect-plc-to-ethernet-ip/19205/1 "2022-02-11T12:58:09Z")

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Error while trying to connect PLC to EtherNet/IP.

I am receiving the following error on the polyscope after trying to connect PLC to the robot. I have currently also another URcap installed that makes use the RTDE interface, the XML-RPC interface and a lot of other connections opened. However i am receiving the following error:

 ![image](https://us1.discourse-cdn.com/flex020/uploads/universal_robots/original/2X/a/a9bc6de9065b621a8637be018f4e15e0e8a424dc.jpeg)

I tried to SSH into the Linux computer on the robot and list all the active ports, you can get a view here:

![image](https://us1.discourse-cdn.com/flex020/uploads/universal_robots/original/2X/6/6b05edc10b225e1137eedc929638f04035f2eb67.jpeg)

If anyone has any ideas to what is causing it i would be thrilled!

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**Author:** ![eric.feldmann](https://avatars.discourse-cdn.com/v4/letter/e/94ad74/32.png) [@eric.feldmann](https://forum.universal-robots.com/u/eric.feldmann)\
**Post date:** [February 11, 2022, 7:12pm UTC](https://forum.universal-robots.com/t/error-while-trying-to-connect-plc-to-ethernet-ip/19205/2 "2022-02-11T19:12:32Z")

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Try uninstalling the CAPs and see if you still get this error. Could be they are allocating IO to the RTDE that should be reserved for the fieldbus communication.

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<div class="post-metadata">

**Author:** ![anon63378011](https://avatars.discourse-cdn.com/v4/letter/a/7ea924/32.png) [@anon63378011](https://forum.universal-robots.com/u/anon63378011)\
**Post date:** [February 14, 2022, 11:13am UTC](https://forum.universal-robots.com/t/error-while-trying-to-connect-plc-to-ethernet-ip/19205/3 "2022-02-14T11:13:27Z")

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Hi!

I figured it had something to do with a python Daemon making use of the RTDE interface. If i turn the daemon off while the normal URcap is running i can connect to the Ethernet IP. Soo, i need both the PLC and the RTDE interface for this problem i am currently trying to solve.

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<div class="post-metadata">

**Author:** ![eric.feldmann](https://avatars.discourse-cdn.com/v4/letter/e/94ad74/32.png) [@eric.feldmann](https://forum.universal-robots.com/u/eric.feldmann)\
**Post date:** [February 14, 2022, 1:23pm UTC](https://forum.universal-robots.com/t/error-while-trying-to-connect-plc-to-ethernet-ip/19205/4 "2022-02-14T13:23:28Z")

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![image](https://us1.discourse-cdn.com/flex020/uploads/universal_robots/original/2X/d/d9ea39ff5c9f6a8e6c9b15aea6fd61b843b4192f.png)

Make sure your python daemon is operating in the right range, as specified in the EthernetIP guide here: [Ethernet IP guide - 18712 - collaborative robots support](https://www.universal-robots.com/articles/ur/interface-communication/ethernet-ip-guide/)