# Random C204A7 errors in URSim simulation

**URL:** <https://forum.universal-robots.com/t/random-c204a7-errors-in-ursim-simulation/24293>\
**Category:** URScript\
**Created:** [October 7, 2022, 1:28pm UTC](https://forum.universal-robots.com/t/random-c204a7-errors-in-ursim-simulation/24293 "2022-10-07T13:28:47Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![csaba.mucsi](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.universal-robots.com/csaba.mucsi/32/277_2.png) [@csaba.mucsi](https://forum.universal-robots.com/u/csaba.mucsi)\
**Post date:** [October 7, 2022, 1:28pm UTC](https://forum.universal-robots.com/t/random-c204a7-errors-in-ursim-simulation/24293/1 "2022-10-07T13:28:47Z")

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Hi,

Sometimes we get C204A7 error randomly while running a robot program in URSim simulator (Polyscope version 5.12.4)  
 ![ProtectiveStopC204A7](https://us1.discourse-cdn.com/flex020/uploads/universal_robots/original/2X/3/3cca55178868da6ed74bcec67cfac20f8c84a3b7.png)  
In the Log window there is a warning for each joint:

 ![Screenshot 2022-10-07 at 14.48.56](https://us1.discourse-cdn.com/flex020/uploads/universal_robots/original/2X/b/be67294e75f7d0e51a06eee0079c714d629c7060.png)  
Also in URControl.log there are warnings about unrealistic torque levels:

```auto
2022-10-07_13:37:37:00216 00:21:56:174 WARNING - checkForPositionAndVelocityInconsistency
2022-10-07_13:37:37:00220 00:21:56:174 WARNING - Target torque level exceeds limit (Joint: 0) while executing program line 23 (script line 3821). Target=-2690.264490 N*m. Limit=330.000000 N*m
2022-10-07_13:37:37:00221 00:21:56:174 WARNING - Target torque level exceeds limit (Joint: 1) while executing program line 23 (script line 3821). Target=452.814209 N*m. Limit=330.000000 N*m
2022-10-07_13:37:37:00222 00:21:56:174 WARNING - Target torque level exceeds limit (Joint: 2) while executing program line 23 (script line 3821). Target=-2467.475776 N*m. Limit=150.000000 N*m
2022-10-07_13:37:37:00223 00:21:56:174 WARNING - Target torque level exceeds limit (Joint: 3) while executing program line 23 (script line 3821). Target=-199.063211 N*m. Limit=54.000000 N*m
2022-10-07_13:37:37:00223 00:21:56:174 WARNING - Target torque level exceeds limit (Joint: 4) while executing program line 23 (script line 3821). Target=-180.922914 N*m. Limit=54.000000 N*m
2022-10-07_13:37:37:00224 00:21:56:174 WARNING - Target torque level exceeds limit (Joint: 5) while executing program line 23 (script line 3821). Target=-65.784121 N*m. Limit=54.000000 N*m
2022-10-07_13:37:37:00225 00:21:56:176 ERROR - acceleration check failed , joint 2, qdd 443.453737, max 40.000000
2022-10-07_13:37:37:00226 00:21:56:176 ERROR - acceleration check failed , joint 3, qdd -294.526639, max 40.000000
2022-10-07_13:37:37:00227 00:21:56:176 ERROR - SanityErrorArgument: 7 ProgramStoppingOrStopped: 0 IsProgramControllingRobot: 1 Timescale: 1.000000

```

As the error occurs randomly, we suspect that it’s somehow related to the currently available CPU resources on the host computer that runs URSim: if the URControl process is not scheduled ‘real time’ by the operating system, some counters may overflow and calculated accelerations become unrealistic. Is this a known issue, and does a workaround exist, e.g. disabling the ‘acceleration check’ in the simulator or improve URSim performance?

Polyscope version is 5.12.4, running on Lubuntu 14.04 in VirtalBox

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<div class="post-metadata">

**Author:** ![csaba.mucsi](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.universal-robots.com/csaba.mucsi/32/277_2.png) [@csaba.mucsi](https://forum.universal-robots.com/u/csaba.mucsi)\
**Post date:** [October 10, 2022, 9:08am UTC](https://forum.universal-robots.com/t/random-c204a7-errors-in-ursim-simulation/24293/2 "2022-10-10T09:08:14Z")

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UPDATE: the error is somehow related to the blend radius between waypoints. Using smaller blend radius seems to eliminate the issue. This can be a temporary fix for now.