Non-Voltage Input

No specific experience of Keyence vision system

But I'd interpret a zero volt input as a make break pair of contacts (e.g. a relay).

At least that would be a safe thing to try.

I've provided a zero volt outputs to builidng management systems (from a drain dosing unit to warn of 'no chemical' ) and it is just a pair of relay contacts.

Good luck

Del

Thanks for your swift reply. Anyone else?

Al

Hi Al,

I agree with the relay story. The only other check you could do, to cover the last .1% of risk, is to get the exact model number and go to the manufacturer's documentation that has detail to the level of the input and output signal specifications of the unit. They probably have a schematic of the input circuity. pdfs of this stuff have to be on their website.

Zero volts and shorting the input with the relay contacts are the same thing. No worries, use the relay or switch contacts or a FET solid state relay. You don't say how fast the trigger must be processed; mechanical relays are generally 10's of milliseconds).

Hugh

I've used the Keyence Vision systems (a year ago) and the dry contact sounds right to me but all my stuff is at the office to verify. At the very least you won't hurt it.

Your description of the input is different than most descriptions from those who are familiar with electronics, but I think taking the input to ground will trigger it. Try it and see -- it won't hurt it since it's an input.

What is the model number for the unit?

Yes I have used the Keyence vision system, and yes, a pulse down to zero does trigger the image. I simply use an open-collector of an NPN transistor across the input terminals.

Here is a partial circuit that has been running for about 3 years with no problem. We are making tiny honeycomb, taking a picture once as each cell is welded, which essentially creates a strobe, so we can see the moving material. The red wire connected to the trigger input also triggers the weld; unfortunately I don't have the complete circuit, and the device is at a different plant than my current location, so I'm not sure if the positive voltage was provided by the internal pull-up of the Keyence, or by a separate one at the welder, or possibly both.

I should be at that plant Saturday 6/9 afternoon or Sunday , so if you get in a crunch, send me a message.

Dick

We have several simple switch inputs( microswitches) in our system to an NPN microcontroller. One lead of the switch is connected to common(0 volts, ground) and the other to the controller input pin.

I would just like to say thanks to everyone for their contributions. The vision system is now up, running and being evaluated before full commisioning into production. Early signs look very promising.

Thanks again to you all.

Alan