Watchdog error expected but not visible with an Robotiq Gripper URCap

Hi everyone,

I have written an URScript which set a watchdog with

rtde_set_watchdog("input_int_register_47", 1, "stop")

Usually, I have an error quickly after pressing play if I do no send any data to the URsim via RTDE.
But when I install the robotiq 2F-85 gripper URCap, I do not have the error anymore. The scripts continue running.

With the URCap I do not see the URScript error as well. If I set the register number to 48, which is not available, I don’t have any error either.

In the logs I can also see the following error:

RTMachine      socket_read_byte_list(): timeout 

I tried two different version of the Robotiq grippers urcap: 1.6.0.4 and 1.7.1.2 , and got the same results.
I am running under Windows 10 with the URSim in the virtual machine of the 1.6 sdk starter kit.

Does anybody have an idea of the reason why I do not see the watchdog error ?
Is it because I am running on URSim without any physical gripper ?

I have tested with the starter kit for 1.7 sdk and got the same behaviour : with the same script I have a watchdog error without the URCap and the URScritp is stopped, with the URCap no error and the URScript is running.

It seems that the absence of error was due to the absence of gripper on the URSim. Therefore, the script was not really running and not showing a watchdog error.
I do not have the same behavior on a real UR10e with the Robotiq gripper plugged on it.