Two of our teams from our school experienced problems at a tournament they attended yesterday. They were both running robotC 3.54.

What basically happened was at random points during the match, their robot would become unresponsive and the motors would continue at their original power.

However, this only seemed to happen on the USB based competition switch. They had been working with the stand-alone competition switch all week with no problems. I have come to believe that this is a problem with the Integrated Motor Encoders. Somehow the I2C communication is interfering with the competition control and taking out the User Microprocessor.

We are hosting a tournament next Saturday and don't want this problem to come up at the tournament.

Has anyone else been able to reproduce it?

(orignally posted: http://www.vexforum.com/showthread.php?t=75487)

It's possible that the wiring to Samantha was not secure; if the robot looses connection to the FCS (because of a collision, for example), the motors will continue running at the same speeds for a few seconds.

This is VEX, not FTC.

Just to give an update; this particular issue has been attributed to the build up of static electricity during the matches, eventually resulting in ESD that was crashing the user processor (via the I2C port used by the VEX Integrated Motor Encoders). If anyone is having these problems, please look at the original poster's link (to the VEX Forums) for possible solutions and make sure to update your ROBOTC installation to the latest version; ROBOTC 3.59.0 BETA has included a 'watchdog timer' that will reset the user processor in case of a crash, which should help alleviate some of the static electricity issues.

You can find the 3.59 BETA here.