Fixed Rotation Times for Heated/Cooled Substrates

[Seraph042]

I'm designing a device that will expose substrates plasma sprayed with YSZ over various temperature gradients periodically. A CAD drawing model has been attached with what I've got so far.

The way I'm planning on this working is that a shaft will be fitted the holder and a sprocket-chain assembly will be used for power transmission. There will be a heating source and a cooling source placed at the top of the cycle, and 2 cooling sources at the bottom to induce the gradients through the substrates.

My question is, right now this system is designed for continuous rotation so that the sample will get heated for however long the heating source is over it, and the rest of the time it will hit the sample holder (picture attached).
Is there a way for me to design a system such that the disk will rotate to the next sample, then stop rotating for some amount of time, then rotate to the next sample (etc) so that the sample heating/cooling will be maximized and the actual sample holder won't be exposed to as much heating and cooling?

 

[optoguy79]

I would probably use limit switches to trip a time programable relay. the motor would turn until it triped a limit switch. That would trigger a relay for the set time. Connect the motor control signal to the normally closed side of the relay. Then once the timer goes off the the relay opens and the normally open motor signal will drive the motor to the next sample, where you will have a limit switch ready to stop it.