Galeon, the phrase 'not taking power from the the loop to energise the magnet' leads me to surmise it must use the now popular method of two magnets north on to south, one of which is then physically twisted to create a 'same pole to same pole' effect to cause the release action.
But power is needed from somewhere to twist the magnet, And if this doesn't come from the loop, where does it come from? Also if this power is not 'stored' in some way then surely it wouldn't be available on a loop disconnection fault. If it is 'stored' how reliable is this storage?
The 'twisting' action possibly uses a motor. Does the motor ever interfere with the data communication?
Obviously, the unit takes power from the loop (if not to keep the magnet energised) at some point. Also further power must be taken to operate the addressable communitcation part of the device. If it really took no power, or even very little power, the maximum number on a loop wouldn't be restricted to 20!
For 'total' fault monitoring the unit would also automatically release on 'loss of data' on the loop. Does it do this?
Don't get me wrong. I'm not being critical of something I know nothing about. I like the sound of it. It could be very useful. I'm just trying to find out the probablity of being able to use these devices in a practical manner taking into account BS7273 etc..