Electric gates

[david.cawkwell]

Hello,

Has anyone any experience of installing electric gates.

I have bought a pair of openers these fit to the bottom of the gates and the box is underground and has an arm in the middle. Smaron is the name.

I have put these out and connected up on a work bench to test. The gate openers do open and close fine. But it seems they never open and close by the same amount. So don't return to the same place each time so the arm is slowly turning through 360 degrees after a number of operations.

The instructions talk about putting a stop on the gate so when the gate opens it hits the stop and the motor will cut off (high current draw) but I can't see how the gate will close again and meet up in the middle each time. The instructions don't talk about a stop in the middle between the gates or anything.

There is an adjustment so you can control the time the motor acts for but if it isn't returning to where it started how on earth is it going to work?

Or is the idea that the motor simply runs for longer than is necessary and hits a stop when it opens and a stop when it closes. In which case I need a stop in the middle of the drive or one at the other side of the gate to stops it on it's opening.

[Vass]

did you ask them?

[RubberBiker]

Not a direct answer to your question, but (many) years ago I worked on laboratory equipment that used precision rotational positioning. In addition to the position sensing (by Fraunhofer grating linked to software control) it had two sets of "limit switches". The inner set (also under software control) signalled an approaching collision, and the outer set signalled an imminent collision (hardwired to cut the motor power).

Depending on the type of motors and the controllers, it's possible you could limit the opening in a similar way with microswitches, and if you have one fixed point in the movement at least you won't have cummulative errors on the return to the opposite position. But - if you're using a remote control (and you halt the gates as soon as they're wide-enough open for your vehicle) and/or have infrared sensing (to stop the gates trapping kids/dogs/posties) - you may have the situation of halting the gate part-way through it's movement. Without "absolute" position sensing, you'd have to use the "closed" position to recalibrate it's position - i.e. after any interruption it does return to closed to find it's position. It sounds rather like you have half a gate control kit - and need a kit of sensors and control logic to go with it.

[Jules]

That was my thought, too... sounds like it needs limit switches to kill the power at the appropriate point (but still allow the motor to reverse).

Although in essence I suppose it's just a glorified car elecric window system - I can't remember now if they normally have hard limit switches or just cut power when the mechanism hits the stops and current draw goes through the roof (having that kind of cut-off ability seems like a good idea anyway; I'm not sure I'd want to rely on IR beams or other gadgetry to stop the gates squishing a child/animal)

Plenty of gates seem to have something in the ground at the centre point to close against and which stops them opening too far "the wrong way".

Personally I'd rather just get out of the vehicle and open them manually that bugger about fitting something that's just going to screw up every once in a while ;-)