programable controller? PID ?

[jonnydot]

Hi Guy's I am building an Automatic egg turner for an old incubator .I wish to use an actuator and I need a way to control it .The egg turner is basically a set of stacked cradles that moves 45 degrees through 90 degrees and back again ,this action will need to be controlled so the actuator push's the cradles for a set amount of time slowly to reach a 45 degree angle over approx 1-2 minutes and stop ,sit there for 4 hours and then reverse the procedure (polarity) back through 90 degrees to the opposite 45 degree angle and once again sit for 4 hours and repeat this cycle continuously for about 4 months .I would also need to be able to temporarily halt this action and have the cradle sit in a horizontal position so more eggs can be set and at a push of a button restart the cycle .Having minimal experience with pid controllers I am at a total loss as to what to purchase so I hoped I may get help here ? This is the actuator I am looking at purchasing http://www.motiondynamics.com.au/linear ... 5000n.html The incubator will hold 1350 eggs ,that's about 95 kg + cradle so it would weigh about 120 kg all up but would only need to push and pull half that weight due to balance ,the actuator is probably an over kill but better to be stronger than just strong enough .Many thanks in advance for your time

[pebe]

The actuator you intend to use has built-in limit switches, so a simple changeover relay to change polarity of the applied voltage would be all you need to oscillate the cradles. Periods of 4hours on and 4hours off could be provided by a mains timer – mechanical or electronic – to switch the relay on and off.

But it would not provide for getting the cradles into the horizontal position for loading. That would require remembering whether the relay was energised or not at the time, and manually changing it, then stopping the cradles' movement at the halfway position. It could be done but it would be a bit ‘messy’.

A much better arrangement would be to use a small 8pin PIC micro controller. Only a simple program would be required. Are you familiar with them?

[jonnydot]

No not familiar at all ,unfortunately I have no electronics experience ,could you provide a link to someone that could supply? many thanks Jon

[jonnydot]

I have one of these could it be used as a timer? http://www.auberins.com/index.php?main_ ... cts_id=115

[pebe]

Unfortunately the relay you suggested does not appear to handle repeated delays.

Re. a supplier. Where do you live?

[jonnydot]

I live in Lismore New South Wales Australia 2480

[pebe]

The timing and switching of the actuator could be done with a PIC micro and four FETs. I could program one for you and ship it to you at cost price. If I gave you a circuit could you assemble the unit?

[jonnydot]

Wow that's an incredibly kind offer !:-) Unfortunately I would have no idea how to build it http://ahsworkshop.blogspot.com.au/p/li ... kema.htmlI have found this but as yet can not get a reply from them?

[pebe]

That's a pity. I tried your link but this came up;

"Sorry, the page you were looking for in this blog does not exist."

[jonnydot]

Try this link ... http://www.google.com.au/url?sa=t&rct=j ... Gc&cad=rja ............. I also found this do you feel it is up to the task ? ... http://www.ebay.co.uk/itm/DC-MOTOR-REVE ... gory=36328

[pebe]

Re: http://www.google.com.au/url?sa=t&rct=j ... Gc&cad=rja
The description of that actuator is rather short on detail. There is no current specified for the motor, and I don’t understand their ‘control module box with selectable fuse bits’. It doesn’t say whether it handles the timing periods.

This one you showed in your first post would appear to do the job and the details are known. http://www.motiondynamics.com.au/linear ... 5000n.html

Re: http://www.ebay.co.uk/itm/DC-MOTOR-REVE ... gory=36328
The timer in this link is a standard 555 timer; it only gives times of 300sec and 700sec, but you need 40min. You could not extend those times because it would require larger caps and/or larger timing resistors. Larger caps have higher leakage currents so under those conditions, timing becomes erratic. Also, it can only switch 2A whereas the MD actuator requires 6A.

[BenJons01]

Thank you for your excellent information.