VM147 Counting on a +12V Pulse


Trying to use the VM147 with the PMK111 for two different devices. I need the relay output to close on two different commons: ground and a +12v signal. I ran a small two position switch into the common wire so that when the switch is in position one the relay connects to ground, and when the switch is in position two it connects to a +12V source.

The issue is that the counter only counts when the common in connected to ground. When I flip the switch to the positive, the relay still trips, but the counter doesn’t continue counting. It’s as though the VM147 can’t see the +12V pulse.

Is this in the programing for the VM147? Is it only looking for a ‘low’ pulse?

Any help would be greatly appreciated.

Hello !

I wouldn’t recommend applying 12 volts to any input og the VM 147 module, and as you
have already observed, it doesn’t work either.

A solution could be to obtain a reed relay and a 2-pole switch instead.

One side of the coil goes to ground, the other side goes to N.O. of MK 111’s relay.

N.O. on reed relay goes to ground. Pole # 1 of the switch in the same way that the
old one was connected in advance.

Pole # 2: When switch is in position 1, the common connects to N.O. of MK 111 /
“top side” of coil on reed relay.

When in position 2, the common connects to common on the reed relay, and thereby
retrieves the wanted ground, every time the relay on MK 111 is energized.

It wouldn’t hurt to connect a little diode across the coil of the reed relay.