Using joystick with onboard program : problem with limit switch

[Jochen]

Still, whatever you decide to do, it's always a good idea to run a program that checks for modal errors on the computer that hosts the motion board as there could be also other situations that could result in a modal error which are not covered by deactivating the limit switches.

Jochen

[JWfee]

I know this post is old, but I'd like to add a question here.  If the monitoring of model errors is done in a "while loop" in labview, will it be fast enough to send a halt command to the motor to prevent a "freewheeling" state.

I had a rather disconserting event occur recently.  I was going along merrily doing contour, onboard, moves with a 7344 motion controller.  Suddenly an error -70035 popped up and the motor, under the force of gravity, slammed into the end stop.   Fortunately I was in a test mode and had large foam rubber bumpers in place, so nothing disastorous happened.  This is a piece of medical test equipment and COULD have injured someone.

Thanks,
Jim Fee

[Brian_Beal]

Does this axis have a brake on it?

[JWfee]

No, there is no break....perhaps there should be.

Jim Fee

[Brian_Beal]

Absolutely!  The brake should be wired to a "drive enabled" output, so that whenever the drive is not enabled, the brake is engaged.  If there are errors on the controller or drive, the drive should be disabled (this is a firmware function), and hence the brake would engage.