OK, I asked this once before, and got some good leads, but none of them
worked out, and now its the 11th hour.

I have a 2 wire instrument that is loop powered at 24 VDC (the current
on the loop varies 4-20mA at 24 VDC depending on the output of the
probe).  I need to monitor the loop and trip a relay at a certain (adjustableurr
ent.

Sure, I could design a thing with a series resistor and monitor the
voltage with a couple of op-amps, but prefer an off the shelf solution.

email direct hcooper@es.com