Question

I am working on a project where I need to close the solenoid valve (24DCV) at a different rate of time (variable closer time). It needs close very fast (at least within 50ms). I am using NI DAQ: USB-6211. Which relay should I use? Will digital relay timer work? Looking forward to your suggestions.

Answer 1

Looking at the details provided and your requirement, I would suggest you to use OPTOCOUPLER or OPTOISOLATERS in place of relays. Also relays are outdated presently.

Optocoupler is an electronic component that transmitting electrical signals between two independent or isolated circuits. Sometimes known as opto-isolator, photo-coupler or optical isolator.

They are of two types:

1. DC-DC optocoupler - they are used for controlling one DC circuit through the other and both having different voltage levels. (which is your case).

2. DC - AC optocoupler - they are used for controlling AC circuits or devices through DC circuits.

Advantages of optocouplers are:-

1. Compact and small in size.
2. It provides isolation between two different voltage circuits.
3. Operation is faster (10 micro seconds) than relays.
4. Can control switching of any device easily from one circuit to the other.
5. Cheap and easily available.
6. Efficient and longer life.
7. Simple to connect in the circuits.

Schematic of DC-DC optocoupler  

In this, connect the signals from your DAQ in circuit1, and connect your solenoid valve in circuit 2.  

Some of the commonly used DC -DC optocouplers are 4N35, PC817. Look for their datasheets which will provide you all the details about these devices.