# Setting input registers with RTDE and reading them in a URCap GUI?

**URL:** <https://forum.universal-robots.com/t/setting-input-registers-with-rtde-and-reading-them-in-a-urcap-gui/12636>\
**Category:** URCap Development\
**Created:** [March 1, 2021, 5:20pm UTC](https://forum.universal-robots.com/t/setting-input-registers-with-rtde-and-reading-them-in-a-urcap-gui/12636 "2021-03-01T17:20:11Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![anon37455377](https://avatars.discourse-cdn.com/v4/letter/a/bc79bd/32.png) [@anon37455377](https://forum.universal-robots.com/u/anon37455377)\
**Post date:** [March 1, 2021, 5:20pm UTC](https://forum.universal-robots.com/t/setting-input-registers-with-rtde-and-reading-them-in-a-urcap-gui/12636/1 "2021-03-01T17:20:11Z")

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Hello,

I’m working my way through tutorials and such still but am stuck on how something like the [python RTDE](https://www.universal-robots.com/articles/ur/interface-communication/real-time-data-exchange-rtde-guide/) (python download at bottom) script would interact with a URCap.

My understanding is that the script `example_control_loop.py` is writing to input double registers. Is it possible to read these values from within a URCap node view with a button callback for instance?

My end goal is to have my external system post values to the UR registers, then the operator could see these values on the urcap gui before executing the program…

Any help correcting my understanding of how RTDE and URCap work together or how I would read the registers from the node view would be very helpful.

Thanks!

Edit: I have just found Fujikit’s monitor… it seems to do something like this I would need to implement the RTDE interface in Java as is [done here](https://github.com/t-fujiki/com.takaaki.urcap.eipmonitor/blob/3cb07e7a95fbdca102de398fbe93961f2311c6c1/src/main/java/com/takaaki/urcap/eipmonitor/impl/rtde/RTDEClient.java)?

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**Author:** ![anon37455377](https://avatars.discourse-cdn.com/v4/letter/a/bc79bd/32.png) [@anon37455377](https://forum.universal-robots.com/u/anon37455377)\
**Post date:** [March 2, 2021, 10:30pm UTC](https://forum.universal-robots.com/t/setting-input-registers-with-rtde-and-reading-them-in-a-urcap-gui/12636/2 "2021-03-02T22:30:52Z")

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Using the RTDE part of [eipmonitor repo](https://github.com/t-fujiki/com.takaaki.urcap.eipmonitor/tree/master/src/main/java/com/takaaki/urcap/eipmonitor/impl/rtde) that @fujikit made was indeed the answer.

I made a new class for my needs based on the example of RTDEClientOfDoubleRegister class and was able to read the registers very easily. Awesome work @fujikit!

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**Author:** ![system](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.universal-robots.com/system/32/1_2.png) [@system](https://forum.universal-robots.com/u/system)\
**Post date:** [March 12, 2021, 2:49pm UTC](https://forum.universal-robots.com/t/setting-input-registers-with-rtde-and-reading-them-in-a-urcap-gui/12636/3 "2021-03-12T14:49:51Z")

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Closed on March 12, 2021, 2:49pm UTC

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