L6470 ext switch-SW-erratic behavior

[dibyajyoti]

Posted on November 30, 2016 at 08:24

The releaseSW command is behaving erratically.

We have our own PCB based on ST design. On Power up GoUntil is executed. Limit Switch used is Omron EE-SX951-W. GoUntil never fails and SW input is detected correctly all the time.After GoUntil, ReleaseSW and Move are executed. Sometimes (unpredictably) ReleaseSW and Move are not executed. Appreciate inputs for trouble-shooting this behavior.   

[Enrico Poli]

Posted on January 20, 2017 at 10:53

When the algorithm fail, are both ReleaseSW and Move not executed?

I suggest you to check the following:

- The SW_MODE you set. By default a falling edge on the SW input causes an abrupt stop of the motor (hard-stop).

- The status of the SW input before you send the ReleaseSW command. The ReleaseSW stops the motor only at the SW input

RISING EDGE

. If the SW input is high, the command continues driving the motor (at very very low speed) until it falls low ad then returns high.

- The status of the BUSY pin/flag before sending the Move command. It is not possible to send a move when the device is busy.