VM110 output voltage problem

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1

Hello

I have a problem with my VM110 interface cart which I use for inputs, to control a buzzer and to control two 12VDC relays.
I connected the relays as instructed in the manual and like I did in earlier projects. The interface cart was able to control the relay like it was supposed to be in an early test stage of the project. In a later stage, I began to experience some problems.

When I activate the output, the relay switches on like it is supposed to be. I measure 12VDC over the relay’s coil. Everything is fine so far! When I deactivate the output again, the relay does not switches off. I still measure 3 to 6V over the coil which is probably too high to make the relay switch off. The led’s on the cart are still working as they are supposed to be.

Is my VM110 broken? What can cause this problem? Any help is welcome :slight_smile:

Thanks!

2

Are all the digital outputs defective?
Did you connect the relay between CLAMP terminal and digital output terminal?
If yes, the transistor array IC4 should not be damaged.

3

Thank you for youre response!

Sorry, I forgot to mention that I am using a VM110N.

Every output of the cart has the same problem. The relay is connected between the clamp and the digital output. I never connected it wrong as far as I know.

4

Maybe the transistor array IC4 is defective.
As a test you may replace it with IC2.
What is the coil current of the relays and the current of the buzzer?

5

I will try to replace the IC’s as soon as possible and post the result.
The coil’s of both relais (which both have their own output) is 70mA.
The buzzer is 20mA.