Need a little help with control circuit

I'm building a device that uses a rotary actuator(RA) to rotate a part

180 degrees. I have a 5 port, 2 position air control valve that I wish to use to direct the air to the actuator. The control valve(CV) is actuated by a 24vdc signal. I can signal the right side of the CV and get air to the rotary actuator causing the RA to rotate CCW. If I send the signal to the left side of the CV the RA rotates CW. The RA has two position sensor switchs. One that closes at full CW and one that closes at full CCW (or at 0 degrees and 180 degrees).

I attempted to wire up the device and when I applied power the RA kept shuttling CW/CCW/CW/CCW. Very impressive but not the desired action.(If anyone very needs to build an air powered wind shield washer let me know, I have the circuit all worked out).

I have a 24vdc signal coming from a clamp solenoid on the main part of the machine. What I need, is a 24 VDC DPDT switch or relay that when the clamp solenoid receives the unclamp signal, the DPDT switch or relay closes one set of contacts allowing current to go to one side of the CV and when it receives the next unclamp signal the DPDT Switch or relay opens the first set of contacts and closes the second set of contacts allowing the current to the other side of the CV. This action of opening one set of contacts and closing the other with just 1 24vdc signal is what I am trying to work out.

I any of you know of a simple and bullet proof way to accomplish this, please let me know.

Thanks Greg Postma

Reply to
Gjpostma
Loading thread data ...

The simplest way I can think of is to use a latching relay.

From Wikipedia... "A latching relay has two relaxed states (bistable). These are also called 'keep' relays. When the current is switched off, the relay remains in its last state. This is achieved with a solenoid operating a ratchet and cam mechanism, or by having two opposing coils with an over-center spring or permanent magnet to hold the armature and contacts in position while the coil is relaxed, or with a remnant core. In the ratchet and cam example, the first pulse to the coil turns the relay on and the second pulse turns it off. In the two coil example, a pulse to one coil turns the relay on and a pulse to the opposite coil turns the relay off. This type of relay has the advantage that it consumes power only for an instant, while it is being switched, and it retains its last setting across a power outage."

formatting link
see McMaster p.864

I think the simplest solution would be a single coil 24VDC latching relay, but I didn't see exactly that in the above links. If you can't find a suitable single coil relay, then I think (without thinking too hard) a dual coil unit with an extra set of contacts to select the appropriate coil to flip the relay's state would do the trick.

Ned Simmons

Reply to
news

Thanks Ned. Latching relays were suggested by a friend on mine, but not knowing how they work I wasn't going to jump into getting one.

After I posted, I spoke with an engineer friend of mine and he suggested an "alternating relay". So I did a little checking and I think I found what I need in a Magnecraft 711XBXCL-24D

formatting link
It seems to be able to do what I need.

Thanks for you help, Ned

Reply to
Gjpostma

That appears to be functionally the same as the Automation Direct single coil latching relay, except with the appropriate 24VDC coil. I've never heard them referred to as alternating relays, so I learned something too. Good deal.

Ned Simmons

Reply to
news

Reply to
JR North

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.