PID Controllers - What do they cost?
- Thread starter gnmontey
- Start date
vagrantviking
CGN Ultra frequent flyer
- Location
- High River, Alberta
I think the last one I bought the parts from Amazon and built was about $40-$50.
You need a relay (ideally with heat sink), and a handful of wire, switches, box, plug receptacle too if you want to get fancy.
You need a relay (ideally with heat sink), and a handful of wire, switches, box, plug receptacle too if you want to get fancy.
If you type in PID controller kit ($29.99), it has the required relay. The thermocouple looks too short, but there are 100 mm one for $5.
You should put it in a box for safety (electrical connections). I have not modified my pot, but have made temperature controlled irons with the same type of controller.
You should put it in a box for safety (electrical connections). I have not modified my pot, but have made temperature controlled irons with the same type of controller.
solid state relay, not a regular one.
Cheaper to build your own if your okay following a wiring diagram, lots of videos on youtube. i built my own for $40 a few years ago. i need to build some more for my molds to preheat on as well to aid in making beer.
basically yes, but it will also learn over time how long to keep the pot on to keep the temperature very close to the set point.
Well.... after looking through some wiring diagrams I see this is more of a packaging challenge than a technical challenge.
Is the SSR Heat Sink a necessity? My casting sessions don't last more than 3 hours at a time.
Thanks,
M
Is the SSR Heat Sink a necessity? My casting sessions don't last more than 3 hours at a time.
Thanks,
M
That would depend on the power rating of your pot vs the rated power of the ssr. I put a heat sink on mine and it doesn’t get hot at all. I don’t think I really needed it. I was concerned that the cheap SSR I bought was not actually good for what it was rated for. I think it would have been fine.
I put one together for about $50 with the solid state relay, heat sink, and probe included. The packaging is the challenge, but once together the unit works great for keeping the pot temp where you want it. I used and old electronics chassis from a serial cable switch. It helps to be a ham radio nut with lots of junk to draw from. I have the Lee 20lb. pot, 115 vac.
They're also very good for keeping the still just above the 163 degree F. boiling point for ethanol, if one were wanting to make a homemade still. You could reuse the controller with another $5 probe. At least that's what I heard.
They're also very good for keeping the still just above the 163 degree F. boiling point for ethanol, if one were wanting to make a homemade still. You could reuse the controller with another $5 probe. At least that's what I heard.
vagrantviking
CGN Ultra frequent flyer
- Location
- High River, Alberta
It's a pretty simple project and more about the packaging as mentioned.
I'm pretty sure that the heat sink is unnecessary in most cases. Could probably just mount the relay to the metal case and let that absorb the little heat that might be generated.
I'm pretty sure that the heat sink is unnecessary in most cases. Could probably just mount the relay to the metal case and let that absorb the little heat that might be generated.
If you ok with wiring things i would just build it. also for a heat sink the next time you see any tower computer at the side of the road you can grab the heatsink from the cpu and mount it to the ssr. mine is massively oversized and barely gets warm.
Mine is a 120V Lee 20lb production pot. Power = Voltage X Current. If yours is 700W the ~ max current draw is 6.4 Amps. For the cost difference on Amazon you could just buy the 40A SSR’s and have plenty of heat dissipation built right in.
The 40A rating on them is at minim spec’d Voltage. It should be good for 24VX40A=960W
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vagrantviking
CGN Ultra frequent flyer
- Location
- High River, Alberta
Yes. Once it's put together it's almost too simple. Set the temp you want on the PID, crank the pot dial to max and start casting when the measured temp matches the target temp. Mine remembers the last settings and I forget how to change the target because I touch it so seldom.
Varies by less than 5C most of the time so there's very little weight variation.
It would be worth it to secure the SSR directly to the enclosure if it’s steel. It will act as a heatsink and extend the life of the SSR.
Going back to finding a scrap computer for the heatsink you can also use the power supply as a housing for the pid, here are some pictures of my setup.
The ssr is attached to the heatsink which is screwed to the metal case. i reused the power input from the power supply i used to make the case. i added the power switch and outlet.
i used a 2 prong plug to attach different thermocouples pending what i wanted to do with it.
Most recently i used it to keep a planter at 32c to get a head start on growing some habenaro's for this summer. i had a stick heater in the bottom of the pot and a thermocouple a few inches above it. worked perfectly.
The ssr is attached to the heatsink which is screwed to the metal case. i reused the power input from the power supply i used to make the case. i added the power switch and outlet.
i used a 2 prong plug to attach different thermocouples pending what i wanted to do with it.
Most recently i used it to keep a planter at 32c to get a head start on growing some habenaro's for this summer. i had a stick heater in the bottom of the pot and a thermocouple a few inches above it. worked perfectly.
Ya a PC PS housing crossed my mind as well, input power plug, on/off switch what more could you ask for.
Sheesh..... how many of those things have I trashed in my lifetime. Nothing here now.
Not sure Value Village has that kind of stuff either. May have to go have a look see.
M
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Almost there. Waiting on a long stem thermocouple that appears to be on the slow boat from China before buttoning her up.
Had an old 6/9 volt power supply laying around from the slot car days (remember slot cars?), that provided a workable PID housing.
Setup seems to do a pretty good job of maintaining the temperature of a light bulb.
Cost a whole $30. Was a fun project and not at all difficult to piece together.
Question: Should this thing remember it's Auto Tune parameters or do you need to Auto Tune after each power up?
M
