REX-C100 PID (cheapest PID on ebay)

[Brewing Clamper]

... The REX-C100 doesn't have that sort of control.

So I'm thinking of doing a single vessel system from my current 4500W e-keggle. I was thinking of using this thing as a temp controller for BIAB mashing then ramping it up to a boil and controlling the boil with it... I won't be able to dial it down if the boil is too strong?

 

[Walker]

So I'm thinking of doing a single vessel system from my current 4500W e-keggle. I was thinking of using this thing as a temp controller for BIAB mashing then ramping it up to a boil and controlling the boil with it... I won't be able to dial it down if the boil is too strong?

correct. this is purely a temperature controller. a boiling kettle has a constant temp, and it doesn't matter if it's a gentle simmer or a violent geyser.\

You will not be able to control the strength of the boil with this controller.

 

[Brewing Clamper]

Hmm... guess it's back to the drawing board. I'm basically thinking of building something like the Braumeister single vessel thing. I currently use a home built PWM to control the boiling kettle but no accurate temp controller...

Hey Walker, can you point me to your controller build thread? I couldn't find it.. Thanks man!

 

[Walker]

Hmm... guess it's back to the drawing board. I'm basically thinking of building something like the Braumeister single vessel thing. I currently use a home built PWM to control the boiling kettle but no accurate temp controller...

Hey Walker, can you point me to your controller build thread? I couldn't find it.. Thanks man!

AH... if you have a PWM already, then you can use the PID for temp control during the mash and then switch over to the PWM for boil control.

that's what I do on my system.

I just have a DPDT switch on the SSR control signals from the PID and the PWM to let me select which device is in control of the SSR.

I don't really have a build thread for my system. There is a thread, but it has very little info in it.

 

[betadave]

I don't think that's what he meant by "duty cycle". On PIDs like the one from Auber, you can adjust that parameter that you are talking about (the output cycle) and then tell the PID to manually drive the output for some percentage of that output cycle. It ignores the temp probe input in that mode.

That sort of duty cycle adjustment allows you to control the strength of a boil by having your element effectively running at a fraction of it's power. The REX-C100 doesn't have that sort of control.

You are right as far as I can tell. To trick the REX into that you would need to adjust the P to some setting and then set the I and D to 0 so the system is proportional only. You can then set the temperature number to something close to the target and the output will be directly proportional to the difference from the PV and the SV. So, if the boiling temperature is 100C, setting it to 102 with a P setting of 20 might give 10% output. Since I don't know if the P sets the error to full output, I am just making that up but it would be easy to find out by trial and error. The P setting would just be wide enough to make control easy. You would have to reprogram to switch back to temperature control. Far too much hassle.

 

[betadave]

I set up a sous vide cooking setup today with my REX C100. I am using the relay driver voltage to run an SSR and using that to run a heating element. It works just fine. I allowed autotune to find the PID settings and after the autotune ran, the temperature is holding at 60. Since I can't see 10ths, I have no idea how close it controls but it cycles on and off without showing anything other than 60 so I assume it is holding within .5C or some rounding would let me see either 59 or 61.

So, basically, the guy on eBay is a skunk but the controller can be used as an SSR controller and get good results if you crack open the case and bring the relay driver voltage out. I don't mind that the relay makes a click as it lets me know it is working. I don't have to look to see the tiny LED.

I am sure that a low budget creative approach will work for controlling the heat rate with the proportional only setting. It would require that you write down the correct P, I, and D numbers so you can reset your unit for temperature control but, in principle, it is fine. It would require some playing but for some P setting, you could control the percentage of on time to match, say, 10 times the degrees over the process temperature that you set your set point. It should be easy to sort out with a stopwatch and five minutes of your tinkering time.

Cool piece of $10 junk. Now I will put it in a case of some sort and allow it to serve as my sous vide cooker for eternity.

 

[ferari12]

I succeeded in using the REX-C100 to operate an SSR also. I removed a relay and ran the switching signal straight to the terminal posts. Here is a PDF with before and after pics: http://www.mediafire.com/?bbqzfm58c7lpsbo

 

[betadave]

Yes, indeed. I built a box from left over floor joists to fit a stainless steel pan that I already owned, insulated it with fiberglass, put in an old 250 watt lab heating pad, installed my modified controller running my SSR in a metal case I had laying around and now I have a very nice sous vide cooker that controls within one degree C. Total cost was around $15. Not bad for a piece of junk. A commercial sous vide cooker of that size would have cost me over $1,000. It is not beer but it makes nice meals to enjoy with my beer. I cooked 4 tri tips at the same time and served 24 people and had left overs with the thing.

Just for the record, I also served american pale ale, brown ale and irish stout at the party. All home brew. Good times.

 

[morzh]

So, basically, the guy on eBay is a skunk but the controller can be used as an SSR controller and get good results if you crack open the case and bring the relay driver voltage out.

Hey guys,

I am new here and just saw that thread - was looking for C100 setup.
But I wanted to tell you this: on ebay those guys sell "M"-type C100 (relay output). However the guy clearly advertised SSR drive output ("V"-type).

Here's what I did - I wrote the guy and he admitted the error in description. I told him I could not use the PID, and first he wanted me to pay him another 15 bucks for the right type. I told him (he sold his for 19 bucks, and the SSR -type sells for 24 bucks) that I will pay him extra 5 bucks.
He agreed and thanked me profusely.
All in all, he was very polite, and only tried to haggle in the beginning.
So I got my SSR drive C100. And, he did not want the other one back, so I have it. Though I have no use for it.

What I mean - ask the buyers if they sell "V"-type (SSR driver) and should they screw you on description - they will pick up the tab. Their fault.
-----


Anyway, I had a question: when using K-type thermocouple (mine is 0-400C) supplied with the PID, initially, until I start heating it up, it shows some negative temperature. Is it the error in the beginning of the range? Anyone noticed that?

 

[morzh]

I succeeded in using the REX-C100 to operate an SSR also. I removed a relay and ran the switching signal straight to the terminal posts. Here is a PDF with before and after pics: http://www.mediafire.com/?bbqzfm58c7lpsbo

Actually I just realize the one I got for the SSR is defective - this is why it measures -55C when it is 25C.
The other one, with the relay output, measures all correctly - boiling water is 100C.

So how did you say you popped up the case? Can't see any tabs. I don't think this Chinese guy will send me another one and I hope to use that relay type as long as I can open it up.

 

[mattd2]

... And, he did not want the other one back, so I have it. Though I have no use for it.

Sorry I can't help with you question, but as for the "unuseful" PID there have been a few people who have converted them to SSR output as I think the control circuit to the internal mech relay is the correct voltage for a SSR, basically as it would go in my head it was open it up - desolder the relay - solder jumers from where the relay control pins were to where the output pins were - close it up and away you go.
Do a search on here first though cause I might be wrong

 

[morzh]

Thanks, mattd2,

I think I'd be able to figure it out once I open the box. Myself I am an EE, so circuitry is no mystery - what's mystery is how to open the dang thing - doesn't seem to want to let me do it to it. The tab I have at the front panel doe not release anything once pressed. And Since this is the last controller I have, I do not want to damage it.

So I solicited help from one of the members here through private message. Maybe I get lucky and he answers.

Cheers and good malting!

 

[betadave]

The configuration menu on the controller lets you add or subtract from the displayed temperature. What I did was put a thermometer in the sous vide cooker I built and just added the few degrees my system needed. From then on the controller did its job. I am not too sure you should ever see a negative temperature as that is a lot of deviation so be careful. Set the controller to the temperature you want and let the system come to equilibrium. Note the difference and then adjust the controller to get that reading. I would then check a few set points and be sure they are good numbers. It is possible that there is a problem with either the controller or the thermocouple. Don't use boiling as the controller is not built for that.

If you want to use it as a boiling control you need to set it for P only and no I or D. Then set the temperature set point a certain number of degrees above the boiling temperature. The output will be a fixed percentage of the difference. Whatever the full bandwidth is should give 100% and then adjusting the delta T down would reduce the percentage. Since boiling point is pretty much a fixed number, you should get steady control. Remember concentration raises boiling point and changes in atmospheric pressure changes boiling point. If you want to go back to regular control you need to put the I and D numbers back and away you go. If I were going to do this, I would buy a second one since they are cheap and not bother with the reprogramming.

 

[ferari12]

Morzh,
I also noticed that the controller reacted quite slowly. I believe that is to preserve the mechanical relay that it is meant to control. However, the unit is not actually as primitive as I first thought. If you go into the settings menu, there is a setting displayed as "ArU" which a "learning" mode. The default value is 0 but if you set it to 1 and then run through a cycle it will set the units parameters automatically to make it work ideally for your system. The heating cycles will become much shorter (in my system they are often less than a second) and generally improve its performance. I've been impressed with the capability of the unit considering how little I paid for it.

 

[betadave]

I opened the case by pushing in two tabs and it pops open as I remember. The cycle time can be adjusted to quite short if you like. Somewhere on the web is the users manual and you can get all the control setting information you need. There is at least one place with a good manual and several that seemed to be short of info. I shortened the cycle time for mine since it is a 500 watt heating pad I use and cycles are of no consequence.

You are right about it is obvious when you open the case. I am a Chem E with an amateur advanced radio license. It took me about one minute with a VOM to identify the holes to wire into (they were already pass through holes and I left the relay clicking as I had no reason to care if it wears out, ever...)

 

[morzh]

Hey guys, thanks for the feedback: I was actually able to open the unit that same day posted here, with a bit more persistence on my part.
De-soldered the relay, completed the mod.

Ferari12,

Yes I did run "ATU" (its autotune) and the operation I described to you was in fact after it was run (it does read ArU - limitations of the 7-segment display).
It works. But the CAL32 I have is more nimble and accurate.

Actually the heating is very fast. The boiler is small. So when the SSR stops and the boiler cools off, after it falls 2 degrees C below (I was trying to go to degrees F, but somehow this controller won't go to the unprotected data setup, the parameter SL2 is the one that controls it) it will then energize the SSR for 2 secs, and it is enough to overshoot by 10 degrees. Of course I don't think water inside jumps that much I measure the temp inside the threaded hole where the thermostat used to go.

I think I should try to do away with Integral part, increase Diff. part and keep playing with Proportional part.

All in all, the two units I received are obviously fake RKCs, and the one that did not work (the one with true SSR control), actually is utterly different from the manual - all parameters' names are different, and the manual is in Chinese.

The real RKC PID will cost at least over 100 bucks, and this one sells for 20.
Well, you get what you pay for.



Betadave,

Yes I have the manual; like I said, it is somewhat helpful with the one I am working with right now (totally useless with the other one). Both units came from the same seller.
On the good side, the insides are so obvious, I did not even have to use the meter to see what pins I have to put out; the only thing I had to do is to, after I did it, measure the polarity, so to know where the + and where the - are. Oh, and I had to run t5o Radio Shack to buy me a vacuum-sucker to desolder the relay. Turned out, some EEs do not have them at home

Cheers!

 

[Walker]

What I mean - ask the buyers if they sell "V"-type (SSR driver) and should they screw you on description - they will pick up the tab. Their fault.

It's not always that easy. Different sellers do things differently.

My friend ended up getting royally screwed and the guy would only refund half of his money and only AFTER my friend gave positive feedback.

 

[mattd2]

It's not always that easy. Different sellers do things differently.

My friend ended up getting royally screwed and the guy would only refund half of his money and only AFTER my friend gave positive feedback.

And I bet the seller also waited for the time that you can change your feedback to elapse before refunding too. Ebay can be a dodgy place It is these guys that make the rating system worthless!

 

[dspano]

Thanks everyone for your posts. I bought two of these PIDs and got burnt by the ebay sellers in Hong Kong. I didn't realize until I finally hooked a 9v battery to terminals 4 and 5 that they were not what I paid for. I soldered in the jumpers on both and now they work like they should. Thanks again! I'll be buying from Auber Instruments next time.

 

[mattd2]

Thanks everyone for your posts. I bought two of these PIDs and got burnt by the ebay sellers in Hong Kong. I didn't realize until I finally hooked a 9v battery to terminals 4 and 5 that they were not what I paid for. I soldered in the jumpers on both and now they work like they should. Thanks again! I'll be buying from Auber Instruments next time.

Did you contact the seller? Seems like a few of them are reasonable in terms of setting things right if you actually ordered the SSR version but they sent the relay ones.

 

[dspano]

Did you contact the seller? Seems like a few of them are reasonable in terms of setting things right if you actually ordered the SSR version but they sent the relay ones.

Sorry for the late reply. I bought these way back in January, so I doubt I'd get my money back. I was finally able to test them this week. For the price, it was worth the ten minutes of soldering. They worked really well.
Now I just have to figure out what the hell I'm gonna brew for my test batch. Lol!

 

[betadave]

I've been using my REX C100 to run my sous vide cooker for about 6 months now. It does a great job. Maybe it isn't making brew but it makes great food to go with the brew.

 

[thargrav]

Even the Japanese ones are really made in China and I can buy them direct from China for less than $30.00 each with shipping.

 

[morzh]

Even the Japanese ones are really made in China and I can buy them direct from China for less than $30.00 each with shipping.

From my own experience - it is not the same.

The ones you buy on e-bay from Hongcong are most of the time counterfeits. They, yes, are PIDs and they work, but they are not in agreement with the REX C100 manual, the names of the variables are different, and one of the two I bought is just totally different and the manual simply does not apply, and another one is kinda in agreement, but only kinda....limited compliance.

Also the guys simply misinforms you.

The one I bought that claimed to be with SSR output was with Relay output, and then when he sent me the one with SSR output - it was 220V one. When I told this to him, he said "no, don't worry, it is universal 110/220V". So when I plugged it in, it lighted up, but the temp measurement did not work, and I thought it was defective. Then I plugged it in 220V and it did work.

It is a mess. But still, I agree - you, most probably, will get something that works, and cheap. But - no guarantee it will, and it is a counterfeit, and even the manual (like the last one I got) may be in Chinese. Of course if you read Chinese - no problem there.

 

[thargrav]

I just talked to my supplier and sure enough, the sample I have coming is only in C but he does state that it has a SSR output as well as a control relay. Also, he does not understand why we need a F scale. I guess I'll keep looking.

 

[morzh]

Well, mine is also in C, and had it been the real thing (not a counterfeit) - it has a variable that changes C to F. But I went through the variables - sure enough, it's not there.

You get what you pay for, but most of the time it is enough.

 

[dspano]

From my own experience - it is not the same.

The ones you buy on e-bay from Hongcong are most of the time counterfeits. They, yes, are PIDs and they work, but they are not in agreement with the REX C100 manual, the names of the variables are different, and one of the two I bought is just totally different and the manual simply does not apply, and another one is kinda in agreement, but only kinda....limited compliance.

Also the guys simply misinforms you.

The one I bought that claimed to be with SSR output was with Relay output, and then when he sent me the one with SSR output - it was 220V one. When I told this to him, he said "no, don't worry, it is universal 110/220V". So when I plugged it in, it lighted up, but the temp measurement did not work, and I thought it was defective. Then I plugged it in 220V and it did work.

It is a mess. But still, I agree - you, most probably, will get something that works, and cheap. But - no guarantee it will, and it is a counterfeit, and even the manual (like the last one I got) may be in Chinese. Of course if you read Chinese - no problem there.

morzh is right. I have one of each. One that says Made in Japan and one that says Made in China. The Chinese version is slightly different, and did not work until I had it running on a 220V circuit. I ended up using it on the boil kettle. I used the Japanese one on my HLT to control the mash because it worked a little better.

You could get the Chinese version working for either though.

 

[thyaguster]

Hi. I found this item on ebay when I was looking for a temperature controller.
I don't really know how a PID works...

This is dual channel, so it means I can connect the heater and the cooler and it controls both?

Thank you.

 

[morzh]

Where's the e-bay link?


A PID is a temperature controller, that has a complex algorithm of controlling a heater (a cooler) using "Proportional, Integral or Derivative" functions - read Wikipedia, if you are interested, it is quite simple.

 

[brewhokie]

Is this the PID in question? Seems too good to be true.

http://www.ebay.com/itm/33067816223...X:IT&_trksid=p3984.m1423.l2649#ht_2249wt_1344