One axis goes slower when homing than others

[Dave_Advent]

My single axis home routine sets velocity to 300 rpm before calling Find Home vi. Two of three axes move to home at that speed, but one axis moves at a very slow speed. It does not change at all when it is changed from 300 RPM. It moves at correct speed when executing a target location move however.

[nestor-sg]

Dave,

Usually when we see this problem it is related to the configuration of the board. Let me explain the process for homing, it will start moving at the speed you set until it finds the "pulse level" (high/low) of the home switch that you set it to look for, after that it will travel at slow speed (1/4 RPS) to re-find it and position in the place you configured it to (start of pulse, etc.). What may be happening here in your case is that the polarity you have set in MAX or in your switch matches each other, so when you call the HOME function it finds it immediately and it travels all the way at very slow speed when trying to find for the second time the switch as I described above.

Please check the polarity or change it in MAX of the Home switch and that should
fix it.

Regards,

Nestor Sanchez
Motion Control Support
National Instruments

[Dave_Advent]

OK! That would fit all the symptoms. I won't get access to the system again til next week, but I am sure you have pointed to the correct area. I was looking for a configuration discrepancy and this is a very likely one.

Thanks,

Dave Fitzpatrick
Project Engineer
Advent Optronics Corp