Electrical Doubt

Hi

I had a doubt in electrical behaviour to DC input module.

The DC input module wiring is of source type, that is the 24V will make the input.

From the 24V power supply +ve is going to the field at the one end of NO Contact, the other end of NO contact is going to Input module which is to be the input of that particular contact.

My doubt is, when i measure the voltage across the two ends of NO contact i am getting 24V how?
In my input Module there is separate 24+ and 24-, which is different from input pin terminal then how can i get 24V across my contact.

How my input terminal acting as 0V.

An open circuit will give you 24V across.
You're measuring across an open contact, which means open circuit.

VigneshGunasekaran said:

The DC input module wiring is of source type, that is the 24V will make the input.

From the 24V power supply +ve is going to the field at the one end of NO Contact, the other end of NO contact is going to Input module which is to be the input of that particular contact.

Click to expand...

If I am understanding your description, you are wiring your input as a sinking input. Is the 24V P/S you speak of seperate from the input card? If you are feeding 24V from an external source to your NO contact in the field, then the input on the card needs to provide the ground for a complete circuit to exist. This would be a sinking input. If the 24V comes from the input card, then the NO contact in the field would need to be wired to ground(common) on the other side to provide the complete circuit when it closes.

I found this site with a quick Google search, you might want to check it out.
http://support.motioneng.com/Hardware/IO/Slice-IO/topic_sink_source.htm

What brand and model is your input card? That would help us answer your question as to which type of circuit you need.