[quote author=Jason King link=topic=67002.msg492012#msg492012 date=1311103239]
i have an interesting problem.
I have an electromagnet that is pwm controlled.
This part is very easy, however. I need to because to sense when it is disconnected.
If it is connected everything is good, if it is disconnected then a i need stop sending the pwm output and raise a warning.
However i have no idea how to do this.
I first though of a current monitor, but there will be times where the pwm will be 0
dos anyone else have any good ideas..??
Kind of a strange requirement, maybe you could explain better why you need to know when the magnet circuit has been 'disconnected' and then have to remove the pwm output. Is there harm having pwm active with an open circuit?
If your requirements needed, perhaps a simple hall-effect switch or even a magnetic reed switch could be mounted on the electromagnet and you could read it as a simple digital input that the magnet is no longer generating a magnetic field?