# Best Practice for driving a valve

For driving a valve based on the datasheet we should limit the max current that flow into the solenoid. If we have an AC valve we should take the inrush current at the start-up into account and apparently for the dc valves we don’t have the inrush current however the DC coil have a higher wattage rating when it’s cold. So again we need more current in the start-up. Having high and low voltage on the solenoid cause the damage and it might burn the valve. If we want to limit the current by inserting a series resistor we should have a high wattage resistor (i.e. having max 2.4 amp for 24vdc we should have 10 ohm resistor – 57W!). How about H-bridges ?

I wonder to know what the best practice for driving a valve (Ac or dc) is. I would be appreciate if you give me some references or book to read.

Thanks

P.S: for this type of valve (Standard 12vdc), Coil resistance is 3 ohm and max current is 2.6 so we should reduce the amount of current somehow.

• You need to post a link to the datasheet. Most solenoid valves are just connected straight to a supply, so there must be something unusual about yours.
– user1844
Oct 23, 2015 at 9:53
• I suspect there is some confusion / error here in the data. I have never, ever, seen a valve sold as a 12V valve which couldn't be run on 12V. People over drive them briefly to get them to open faster, and they under-drive them to reduce power once they're open, but IME you can always run them at their rated voltage.
– user1844
Oct 23, 2015 at 12:26
• Rather than posting a fragment of the data, can you just post the part number or a link to proper information about it?
– user1844
Oct 23, 2015 at 12:31
• Thanks Will for your replies and sorry for the inconvenience I just wanted to make it simpler. here you are, the valve is belong to atos company proportional relief valve type RZMO-AES table F007-21/E. you can get it from this page link Oct 23, 2015 at 12:50
• Right! That makes more sense, though not much more. This is a proportional valve, not a simple solenoid, and the -AES variant has integrated electronics, with a digital communication interface. You're not expected to drive the coil directly - per section 11, you provide 24V and a control signal, and the valve does the rest. You still need to post the full part number to describe exactly what you've got. The coil resistance in that table to posted is just for the -A version, not the -AES
– user1844
Oct 23, 2015 at 12:55

The RZMO-AES is a proportional valve, with an integrated digital control interface (there are several options).

You don't drive a coil directly, you provide 24V power to the valve and then talk to it on a digital interface. You don't need to concern yourself at all with how the coil is driven, that's an internal implementation detail.

There aren't a lot of such drivers. In industry the solenoids are usually excited with constant voltage AC or DC. But indeed, your observation is more then a nonsense question, because I have already thougt to implement this technique to speed up pneumatic valve switching time. I will post you some links: