Universal Robots Forum

Limits of RTDE Clients

How many limits of RTDE Clients to accessing port 30004?
When I tried third clients, their connections were success. But fourth accessing was failure.


Did you test the behavior on a real robot and/or ursim?
In ursim (5.6) I could connect with 5 devices and InstallationNode.

On a real robot I can do a test next week.


Thank you for replying.
I tried on ursim SW3.10.0

I use CB series.

on CB ursim 3.12 I could connect via InstallationNode and 4 times with the example: record.py
Currently we dont have access to a real robot of CB-series

Thank you very much.
I will try the real robot next week too.(UR3)

This is from the release note of Polyscope 5.5 and 3.11

Extended RTDE client limit
Allowing twice the amount of RTDE/fieldbus clients, six in total, which allow interfacing with more devices simultaneously.
Enables users to pursue more advanced applications.

So with ursim 3.10 their is only 3 RTDE client available.


Thank you for replying.
The firmware was updated to SW3.12 and I verified on URSim and Real Robot(UR3).

The result is below:

on URSim(SW3.12): limit is 3
on Real Robot(SW3.12) without Ethernet/IP : limit is 6
on Real Robot(SW3.12) with Ethernet/IP : limit is 5

Host Computer:
Real Robot:

The below image is with Ethernet/IP and it is indicated that limit is 5.