Thanks Jamie and Andrew. Problem solved!!! Shom On Thu, Nov 4, 2010 at 11:36 AM, Patrick & Cari Norton <[log in to unmask] > wrote: > I asked my son about the question posted by Shom Paul. Here is his > answer... > > > *From:* Andrew Norton <[log in to unmask]> > *Sent:* Thursday, November 04, 2010 11:31 AM > *To:* Patrick & Cari Norton <[log in to unmask]> > *Subject:* Re: listserv question > > If "lockup" refers to the condition when a human operator cannot move the > third motor, this is a common problem in menu/master programs. > > When the NXT sets a motor to "break," it locks the motor, preventing it > from turning at all. To get the motor out of "break" mode and into "coast" > mode, use a move block to turn the third motor 1 degree (or something else > small) with the end action set to "coast." Setting the motors to coast > should be done between the end of each mission and the start of the next > one. This problem not seen when running the programs individually, > because the NXT sets the motors to coast at the end of each program. > > The third motor should now move freely between missions. > > However, this will cause another problem: > The NXT keeps track of how the motors are positioned, even while they > coast. The effect is that the arm will move too far/not enough in the next > program. The solution is to reset the rotation sensor before running the > next mission/run. This is done using the yellow rotation sensor block and > setting the action to "reset." > > Andrew Norton > Programmer for FLL team 12, ACME Robotics > www.RoboDesigners.com <http://www.robodesigners.com/> > > ----- Original Message ----- > *From:* Patrick & Cari Norton <[log in to unmask]> > *To:* Andrew Norton <[log in to unmask]> > *Sent:* Thursday, November 04, 2010 11:15 AM > *Subject:* listserv question > > *Subject:* nxt motor lockups *From:* Shom Paul <[log in to unmask]> * > Reply-To:* Shom Paul <[log in to unmask]> *Date:* Wed, 3 Nov 2010 > 13:35:32 -0400 *Content-Type:* multipart/alternative *Parts/Attachments:* [image: > Parts/Attachments] > > *text/plain*<https://listserv.jmu.edu/cgi-bin/wa?A3=ind1011&L=VADCFLL-L&E=0&P=282776&B=--0022158c1a39022926049429788e&T=text%2Fplain;%20charset=ISO-8859-1>(24 lines) , > *text/html*<https://listserv.jmu.edu/cgi-bin/wa?A3=ind1011&L=VADCFLL-L&E=quoted-printable&P=283698&B=--0022158c1a39022926049429788e&T=text%2Fhtml;%20charset=ISO-8859-1&XSS=3>(20 lines) > > Has anyone experienced situation where a motor would lock up when running a > program with multiple myblocks (and nested myblocks)? We're experiencing > this problem with our robot's 3rd motor when we run a master program (where > all our missions are in one program), which we don't see when running the > missions individually. Does anyone have any suggestions? > > Will activation of the 3rd motor on a separate track fix this? Has anyone > found reasons to stay away from using master programs? > > Thanks, > > Shom > > > ------------------------------ > To UNSUBSCRIBE or CHANGE your settings, please visit > https://listserv.jmu.edu/archives/vadcfll-l.html and select "Join or leave > the list". > VADCFLL administrative announcements are sent via VADCFLL-ADMIN-L. Visit > https://listserv.jmu.edu/archives/vadcfll-admin-l.html to subscribe. > -- To UNSUBSCRIBE or CHANGE your settings, please visit https://listserv.jmu.edu/archives/vadcfll-l.html and select "Join or leave the list". -- VADCFLL administrative announcements are sent via VADCFLL-ADMIN-L. Visit https://listserv.jmu.edu/archives/vadcfll-admin-l.html to subscribe.