I would place this across the coil as close to the terminals as possible!
Cheers for the device recommendation! I can't get close to the solenoid terminals unfortunately, these'll be a couple meters away.
You might look up actual data re "slows down closing of the solenoid". How slow is it?
2-msec? 2-sec? As far as effective goes, probably 99% of the time [guesstimate], people
just put the diode in reverse across the coil, so that should say something.
1ms extra opening would be far, far to long in my application - that's why I'm concerned. I'm in the 1% unfortunately. I can't put the device across the coil (I should have mentioned that before!) but I can feed it back into the power supply that feeds the board before the regulators etc, as that ultimately is the same supply that feeds the external solenoids.
I'm not sure if that, or conducting it to ground would be better...