Next little stage complete.
I have completed the build of my automatic voltage controller.
Instead of the most often used circuit where a pot is adjusted via an SSR, I have used a PID temperature controller, with temperature sourced from both the column and boiler. I have used two PID's and control is switched between them via a 3 way switch. LED's illiminate to indicate which PID is controlling the power flow. I didn't want to take the supply off the PID as such as it will be interesting (however, not really useful) to see the temperature of both boiler and column. I also have temperature sensors in the coolant outflows, both Deflag and condenser - just because I could :-B
It has a push button start, or "energisation" button and an emergency stop button which is latched. These are low current rated switches, so I had to connect them to the higher power part of the box via a relay (bottom right in the last photo)
Now, all I have to do is decipher the Chinglish instructions provided from the PID manafacturer (Sestos D1S) so I can get it programmed to reduce power once it gets to my set temperature. With the googling I have been doing, it may take a little while.
The wiring took a bit to work out, but after about 10 separate wiring diagram plans, I got it nailed and it worked first time :o .
I am pretty happy with it, however, the 1m long thermocouples are not quite long enough, so I will be ordering 1.5m long ones to allow a bit of extra room.
Box powered up, switch in the centre position which means no flow of power to the element
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Switch in position 1, say for the boiler temperature control
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Switch in position 2, say for the column temperature control
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The box opened up to see the wiring work done
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I have put test lugs on the back of the box to take the incoming sensor inputs from the four thermocouples to allow for nice, easy, and quick assemble/disassembly. That part was not pictured quite so well though
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