Stc-1000+

[alphaomega]

Thanks Will!

Just remember y'all that this is still very much work in progress. But I need your help testing and suggestions for improvement.

 

[wilconrad]

Thanks Will!

Just remember y'all that this is still very much work in progress. But I need your help testing and suggestions for improvement.

Understood; will cycle some water and take some traces with my BCS rig as soon as I get parts in to see how it performs! Should be fun; will chime in here as soon as I have some results to report.

 

[alphaomega]

On another note, are anybody running the 1.05 version (the one that is in the work branch)? I haven't heard much about it, and I want to bump it to an official release unless someone has any problems with it.
Partly, because I think it is time. No more changes will be made to it unless there are issues and partly because I'd like to use the work branch to push experimental stuff I'm working on (trying to get second tempsensor to fit, which will need some serious shoe horning).

 

[wilconrad]

On another note, are anybody running the 1.05 version (the one that is in the work branch)? I haven't heard much about it, and I want to bump it to an official release unless someone has any problems with it.
Partly, because I think it is time. No more changes will be made to it unless there are issues and partly because I'd like to use the work branch to push experimental stuff I'm working on (trying to get second tempsensor to fit, which will need some serious shoe horning).

Yes, I've been running 1.05 on my setup since it was released, no issues!

 

[alphaomega]

Sweet, thanks!
Then I think I'll move it up and make a proper release for it.

 

[Spellman]

No problems here either, been using it constantly since the day you put it up and everything has been working great!

 

[MikeInMKE]

On another note, are anybody running the 1.05 version (the one that is in the work branch)?

Darn! I just finished flashing two units, one of which is now controlling my keezer (seems to overshoot the setpoint by quite a few degrees).

 

[wilconrad]

seems to overshoot the setpoint by quite a few degrees.

Flashing to 1.05 isn't going to change this, as overshooting is very likely a result of your setup rather than an issue with the controller. STC-1000+ is not a PID controller, so some overshoot is inherent, but you can reduce it by securing your temp probe to one of the kegs, or by dropping the probe in a glass of water inside the keezer. Either of these solutions should stabilize the temperature reading.

 

[balrog]

Flashing to 1.05 isn't going to change this, as overshooting is very likely a result of your setup rather than an issue with the controller. STC-1000+ is not a PID controller, so some overshoot is inherent, but you can reduce it by securing your temp probe to one of the kegs, or by dropping the probe in a glass of water inside the keezer. Either of these solutions should stabilize the temperature reading.

Working the overshoot issue myself and I totally agree with setup comment by Wilconrad. Much smaller heater for me did WONDERS for overshoot. It has to do with ambient temp I am sure also. So while it is great now, change of new england seasons may require adjustments for me.

 

[wilconrad]

Working the overshoot issue myself and I totally agree with setup comment by Wilconrad. Much smaller heater for me did WONDERS for overshoot. It has to do with ambient temp I am sure also. So while it is great now, change of new england seasons may require adjustments for me.

Yes, agreed, I had this same problem myself; even a 40W bulb in a paint can was more heat than was needed this past spring. A switch to a 25W bulb did the trick; I suspect that we'll get a lot of questions about this in a few months as Fall approaches.


Sent from my iPhone using Home Brew

 

[MikeInMKE]

What bug fixes / features am I missing with 1.04 versus 1.05? Thank you for all of your work.

I don't have a heater in the keezer, thankfully, or my electric bill from the repeated heating and cooling would break me.

The thermo probe is just hanging free near the bottom of the keezer, so there isn't any thermal mass or insulation to keep it from sensing the ambient temperature within the keezer. I'll have to spend some time watching it to see if it shuts off the compressor the instant it reaches the setpoint, and then see how much lower the remaining pressurized freon brings the fridge as it's pressure returns to equilibrium.

If I place the probe within insulation, or attach thermal mass to it, I suspect it will only lengthen the delay between actual ambient temperature and the reading of it.

To also be considered, I am measuring the temperature of the ambient air within the fridge. Air, being a gas, has very little thermal mass relative to that of fermenters and kegs of beer, so the temperature swings of those liquids should be a fraction.

 

[alphaomega]

The main differences between 1.04 and 1.05 is that the latter will reset both the heating and cooling delays once either a heating or cooling cycle ends (to be able to avoid chasing due to over/undershoot), also heating delay max setting is increased and power off functionality is handled better.

I am afraid to tell you that you've got it all wrong. The air temperature inside the fridge/freezer is irrelevant (well, not totally true, but almost). What you want to control is the temperature of the beer. Yes, the beer has a lot of thermal mass, but that is a good thing for your compressor. There will be a tradeoff between how much temp swing of the beer you are willing to tolerate and how frequently the compressor cycles.
Trust us, you need to tape the probe to the fermenter and insulate it or use a thermowell.

 

[Spellman]

Since you mentioned "keezer" I'm taking that as you are using it for serving rather than fermentation. I would advise putting the probe in a bottle of water or something. You are trying to control the temp of the liquids being stored, not the air. As you are running it now it will cycle much more frequently and shorten the life of your freezer.

 

[wilconrad]

If I place the probe within insulation, or attach thermal mass to it, I suspect it will only lengthen the delay between actual ambient temperature and the reading of it.

That it will, and it will also stabilize the reading. Try it, you'll like it.

 

[MikeInMKE]

Ok, I will try attaching the probe to one of the kegs and watch what happens.

And yes, I'm using the keezer for serving, with it occasionally doing double duty as a lager fermentation and lagering chamber.

It looks like I might want to upgrade to 1.05. Good thing I soldered some headers in.

 

[priest77]

@alphaomega
I've just flashed the firmware with PI control but I can't set it up as I want.
I am using STC-1000 for a chicken incubator and I need temperature to be as stable as it can be at 37.7C, but with this firmware I have only 25.5C max in settings.
What settings should I use to get the temperature steady at 37.7C?
I am also drive it with an SSR.
Thanks!

 

[jleiii]

A few questions for those that have modified their STC-1000's, aside from flashing new code.

Has anyone replaced the relays with a new, or higher capacity one? From some of the posts, it looks like some people have removed the relays and are driving an SSR instead.

I finished up my glycol chiller this weekend and inadvertently crossed a hot and neutral wire in the pump wiring, and as soon as the second STC energized there was 120 volts across 2 relays, and with a bright blue flash and snap, both are fried.

I need to do something a little different anyway since I need my fan to run for hot or cool, plus the pump for cool, so maybe this is a chance to figure that circuit out and not need the internal relays at all.

Any wiring modders out there? For the SSR crowd, what it the relay control voltage?

 

[alphaomega]

@alphaomega
I've just flashed the firmware with PI control but I can't set it up as I want.
I am using STC-1000 for a chicken incubator and I need temperature to be as stable as it can be at 37.7C, but with this firmware I have only 25.5C max in settings.
What settings should I use to get the temperature steady at 37.7C?
I am also drive it with an SSR.
Thanks!

Hi!
Thanks a lot for reporting!
I've checked it out, and while I found a but in the 'Set' menu (that might have affected you actually), I want to make sure you are using the correct settings.
What you want is to use 'constant temperature' run mode that is 'rn' in the 'Set' menu should be set to 'ct'.
Then setpoint, 'SP' should be set to 37.7.
When I checked, SP was able to be set past 25.5, but the bug in the menu made SP value only visible when scrolling up through the items in the menu (but not down).
I have fixed that and pushed the change.
Please, let me know if to still have issues. And please, please, to test this setup well before using it 'for real'. I could live with ruining someones mash (even though that would be bad), but I don't want to be haunted by unborn chicken ghosts

A few questions for those that have modified their STC-1000's, aside from flashing new code.

Has anyone replaced the relays with a new, or higher capacity one? From some of the posts, it looks like some people have removed the relays and are driving an SSR instead.

I finished up my glycol chiller this weekend and inadvertently crossed a hot and neutral wire in the pump wiring, and as soon as the second STC energized there was 120 volts across 2 relays, and with a bright blue flash and snap, both are fried.

I need to do something a little different anyway since I need my fan to run for hot or cool, plus the pump for cool, so maybe this is a chance to figure that circuit out and not need the internal relays at all.

Any wiring modders out there? For the SSR crowd, what it the relay control voltage?

Rewiring for SSR is pretty easy if you are able to solder. All you need to do is desolder the relays and add jumpers from the input pads to the output pads. I believe the STC outputs around 12V to drive the relays and most SSR usually accepts around 5-35V. Just be damn sure to mark the unit well so nobody inadvertently hooks up mains voltage to it again.
I know I have seen a pretty good guide how to do the mod, but I can't seem to find it atm.

 

[jleiii]

Rewiring for SSR is pretty easy if you are able to solder. All you need to do is desolder the relays and add jumpers from the input pads to the output pads. I believe the STC outputs around 12V to drive the relays and most SSR usually accepts around 5-35V. Just be damn sure to mark the unit well so nobody inadvertently hooks up mains voltage to it again.
I know I have seen a pretty good guide how to do the mod, but I can't seem to find it atm.

Been soldering since about 1971, so I'm good with that part! Jumping the relay control to the output makes a lot of sense for me. I can then make my own relay board to fit my needs. Thanks.

 

[priest77]

@alphaomega
Thanks, now I can set SP to 37.7C and don't worry I won't put the eggs in the incubator soon I am only testing it now.


@jleiii
Here is my board. I've removed the (heating) relay and soldered two wires (jumpers) instead:




You can also add some cooler with thermal paste to SSR if it is getting hot:


I hope this will help you!

 

[wbarber69]

Why do you have to remove the relays to wire for ssr. You could just add a header or something in the bottom to break out the low voltage. Or use an AC-AC ssr and use the relay to fire the ssr. Which sounds redundant but it's an option if you need to run a larger amperage.

 

[alphaomega]

Headers will be hard to fit, but sure you could just solder on some wires to bring out of the case. I guess AC-AC SSR would work also.
But IMHO the cleanest solution is to remove the relay and add jumpers. If you are gonna go for SSR, then the relay will not add anything and it will be less of a kludge.
Especially if you expect more frequent switching, the relay might also be kind of annoying to listen to

 

[wbarber69]

I'm totally down with modding it to save space but maybe you want options.

 

[jleiii]

Thanks for the details.

Since I need to power my fan for both heat and cool, bypassing the relays and using an external circuit might be the best option. When I first built my controller (4 stc-1000 in a box), I designed a circuit to handle this situation, but until now did not need it. A quick check on ebay and oh look an opto-isolated 8 gang relay board for $10.67 from NY. Can't beat that price, except from china at only $2 less, but a month for shipping. Looks like the perfect solution, or at least close enough. I'll have to add a few diodes to act as an or gate to energize the fan relays for both cool and heat input. Couldn't be simpler, except that the inputs are common supply voltage, and activated with a low/gnd signal. I'll have to tweak that part, unless the STC is active low as well. That is assuming the circuit diagram on another auction is accurate, as they show the relay coil connections wrong - both coil wires connected together! Can't blame language translation for that.
Time to pull out one of the fried ones and check it out.

 

[alphaomega]

Why not just power the fan from both heat and cool relays? Seems simpler to me.
Edit: Nevermind that... Brainfart. After drawing it up on paper I see how that would not work
But there has to be an easier way. Like an always on fan or one fan for heating and one for cooling.

 

[DrunkleJon]

Wouldnt it just be easier to when wiring the box wire nut branch off the +, -, and ground and add a constant on plug like many of us did with vanilla STC1000's for fans in keezers/ferm chambers? It seems to me that you are making more work for yourself by hardware hacking an always on into it where a simpler wiring solution could be adequate.

 

[jleiii]

Wouldnt it just be easier to when wiring the box wire nut branch off the +, -, and ground and add a constant on plug like many of us did with vanilla STC1000's for fans in keezers/ferm chambers? It seems to me that you are making more work for yourself by hardware hacking an always on into it where a simpler wiring solution could be adequate.

Why not just power the fan from both heat and cool relays? Seems simpler to me.
Edit: Nevermind that... Brainfart. After drawing it up on paper I see how that would not work
But there has to be an easier way. Like an always on fan or one fan for heating and one for cooling.

Not to drag this post away from the core topic, alphaomega's awesome code mods, any more than I have already but I'm not making this any harder than it is. I have 1 fan, in heat mode it alone produces enough heat to keep my fermenter chamber in the 60's during the winter. That same fan now has (in 2 of 4 chambers) a glycol radiator mounted to it for summer cooling. When I need cooling the fan AND glycol pump both have to run. If I leave the fan on all the time, it will add heat I don't need causing the cooling cycle to work more.
The other 2 chambers have a glycol cooling jacket that wraps around the carboy, so no fan needed for cooling here. The radiator alone was not good enough for lagers, 55F for fermenting is possible, but it ran a lot. The cooling jacket took 1.5 days to bring 5 gal from 70 (drest) to 37F using glycol at 30F. I was running the glycol at about 27F, but the radiator froze up from moisture in the air (condensate). I don't think I can get much below about 37 with 30F glycol, based on how long the last 1 degree took.
You can see more about this in this post although I've not updated it for a few days. I'll be adding more in the next day or so.
Update: Other thread updated

 

[alphaomega]

Oh. Yeah. You got some nice gear there
I like that you use the heat generated by the fan. A little heat goes a long way in an enclosed and insulated space.
I guess I can't be of much help here. Using the external relay module might be an easy way forward. If you remove the internal relays and add jumpers, just remember that the stc already includes drivers for the relays, so don't kill the drivers on the new relay board. You might need to add current limiting resistors (if it expects 5v). You could probably use the resistor as the jumper.
Best of luck!

 

[jleiii]

Oh. Yeah. You got some nice gear there
I like that you use the heat generated by the fan. A little heat goes a long way in an enclosed and insulated space.
I guess I can't be of much help here. Using the external relay module might be an easy way forward. If you remove the internal relays and add jumpers, just remember that the stc already includes drivers for the relays, so don't kill the drivers on the new relay board. You might need to add current limiting resistors (if it expects 5v). You could probably use the resistor as the jumper.
Best of luck!

The fans are only 24 watts, but they do the trick. I started with 250w fan mount heaters, and was testing the fan running 100% of the time, and found that the temp rose steadily. I disconnected the heaters, and sure enough even on the coldest days (basement around 50F) they were able to keep up, no problem. Look for these heaters in the Selling forum soon!

The technical details on the relay board is very limited. One ebay seller does have a schematic, but as I noted at least 1 glaring error. The inputs are a series resistor, indicator LED and opto coupler. The board voltage is 12v (or 5v in another model) so I'd assume that the resistor would be for a 12v input (or 5v). No matter, I've got drawers of resistors if I need a different one.

Going this route lends itself to not being able to use the STC1000+ code you've created, or at least not without manual intervention. With the glycol jacket I can't raise the temp for the Drest in a timely manner, and switching to hot glycol is, well, just too far! But then I have 6 STCs that are all the wrong ones anyway.

If the 2 I fried are damaged beyond the relay, then I could replace them with flashed ones (I'm on Will's DIY list), and just leave the jacket open during the drest phase. I'll just have to see where this goes.
Further updates will be on my DIY post, so back to the awesome STC code discussion.

 

[Spellman]

I haven't looked at one in some time, but could the relays from the non-compatible ones replace the fried ones? Provided that was all that was damaged obviously.