Steve Myres, PE
I'm looking for a sensor to detect impending collisions between multiple cranes running on the same ways. I must be able to apply it in a failsafe manner, meaning, in the case of an optical sensor, that if the optics get dirty, power is lost, or wiring is loose, the resulting condition looks to the control system like a crash, rather that concealing a potential one. Preferably not a sensor with an analog output (customer doesn't trust them). Application parameters: Max distance which must be sensed - about 100-200 ft. Approximate "crash" distance - 3-4 ft.