Linear Actuator with no limits

[Basil]

I have a Linear Actuator with no limits. Board was bad in it and I Cant get the board. I looked here and the on the net for a circuit to add in line so it will stop at each end. I have had no luck. Can some one help me with this? I have a Red Rock tracker controller I am going to use with it. The system is 12 volt.

[Old F]

You mite want to go old school an think a long the lines of relay logic .

I have seen some that used only mech switches  for limit an reversing

Old F

[chainsaw]

I also use a couple of the Redrok controllers(work great). All the old sat.dish actuators around here use a couple of micro-switches with adjustment for travel at each end. You could possibly use switches at some physical point of travel on each side of your array for control. Probably not the best solution because of weather exposure. With lots of these old dishes still out there perhaps you could find an actuator with the mechanical switches.

[Basil]

Hi Old F. I was just out in the shed trying that. I thank I have It.

The only draw back I see is if it tracks half way and then no sun to dark. It will set there until the sun catches up with it the next day. Thats better than not working at all. I may figure a way around that later. Old school Saves the day. When put on I will post it and the wiring so others like me can do it. It's not pretty but It's working. I think...

[Basil]

Thanks I am trying that. Having to build it all. It's slow.

[DaveW]

Basil -

  I had much the same problem a while back.  I used an old timer from a non-working coffee maker and set the time to 9:00 PM.  The timer contacts are fed from the Dawn microswitch contacts so that if the tracker has not returned to the dawn position and the timer reaches 9:00 Pm then the tracker is forced to the start position.  Once the tracker faces East the dawn microswitch kills the power to the timer contacts and the system is ready for a new day.  This backup failsafe has worked for about 3 years now.

[Basil]

Thanks Thats what I needed to get the no sun problem out of the way. I will try it as soon as I finish the first part.

[Basil]

Thanks for the help from all of you. This has solved the tracking problames.

No need for more comments unless you just wont to. I will not reply to keep post down. Well if it's real good I may have to jump in.

[tecker]

 Printers have what you need . An optical gate you just need a tab on your mech to match up.

[JW]

   I would imagion that the higher the resolution at (floating)stoping points, could augment a more solid unit. Such as PWM would provide, like you can see on the futaba RC car servo's. 270* on a liner unit is quite versatile, but it would not be 2 axis, unless, it was tied to another (such as/same as)independant system. Its my understanding, this is not a servo control device.

JW

[commanda]

Magnet/reed switch sensors as used in alarm systems. Should be easy to seal with silicon. Mount underneath so the plastic housings are out of the sun.

Amanda

[bob golding]

could try hall effect sensors with magnets. think you can get them with the drive transistor built in to drive a fet to switch a relay. solid state so nothing to  go rusty if you seal them into a box with silicone sealant.

cheers

bob golding

[BigBreaker]

Just a silly question, but why doesn't anyone use time of day anymore? or at least run the motor at the equivalent of one arc sec/second once the sensors "zero in"?  It seems to me like the rising and setting of the sun would be really simple to track.  Clouds seem like a needless distraction.

[Mary B]

Monitor current draw. When the actuator hits either stop the draw will jump.