# UR Simulation TCP/IP Control

**URL:** <https://forum.universal-robots.com/t/ur-simulation-tcp-ip-control/31203>\
**Category:** Technical Questions\
**Created:** [November 2, 2023, 4:11pm UTC](https://forum.universal-robots.com/t/ur-simulation-tcp-ip-control/31203 "2023-11-02T16:11:30Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Adam](https://avatars.discourse-cdn.com/v4/letter/a/4af34b/32.png) [@Adam](https://forum.universal-robots.com/u/Adam)\
**Post date:** [November 2, 2023, 4:11pm UTC](https://forum.universal-robots.com/t/ur-simulation-tcp-ip-control/31203/1 "2023-11-02T16:11:30Z")

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I am currently developing an external controller for the UR3e. Do accelerate development, I have installed and am currently running the UR simulation (see [Universal Robots - Offline Simulator - e-Series - UR Sim for non Linux 5.9.4](https://www.universal-robots.com/download/software-e-series/simulator-non-linux/offline-simulator-e-series-ur-sim-for-non-linux-594/)). I am attempting to send URScript commands to the robot (specifically movel and movej) commands over TCP/IP.

While I am able to read data from the simulated robot (over all ports and the RTDE), I am unable to send commands. The simulator log returns the following error:

C210A0: Socket is read-only when the robot is in local (Teach pendant) control

I have ensured the simulated robot is powered on, enabled remote mode, and switched the GUI to remote mode. Despite these changes the error persists. Has anyone encountered this behavior before?

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**Author:** ![lxop](https://avatars.discourse-cdn.com/v4/letter/l/8491ac/32.png) [@lxop](https://forum.universal-robots.com/u/lxop)\
**Post date:** [November 6, 2023, 7:47pm UTC](https://forum.universal-robots.com/t/ur-simulation-tcp-ip-control/31203/2 "2023-11-06T19:47:08Z")

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Sounds very strange. Do you need to use the version 5.9.4 simulator? If not, you could try a more recent version to see if it’s just a bug in that version.

Other than that, are you sure you’re using the correct IP address for your simulator? You’re not accidentally using the IP address of your actual robot?

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**Author:** ![Adam](https://avatars.discourse-cdn.com/v4/letter/a/4af34b/32.png) [@Adam](https://forum.universal-robots.com/u/Adam)\
**Post date:** [February 11, 2024, 6:35pm UTC](https://forum.universal-robots.com/t/ur-simulation-tcp-ip-control/31203/3 "2024-02-11T18:35:22Z")

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Determined the source of the error. When sending a single-line URScript command over TCP/IP, the command must end with the newline character, ‘\n’.