Where to take temp reading in RIMS setup

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Shred said:
I'm pretty handy, but this is a touch past my previous experience. I have a friend who will be helping as well. He's a "handyman-type".... I know this sounds like an accident waiting to happen, but we're pretty thorough and don't leave anything to question.
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Good. I don't want to be semi responsible for an accident.

The PID should have the SSR built in or is this a component? As far as I can tell from the PIDs I've been shopping, they seem to be part of the unit...
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Its a (slang) terminology thing. Solid State Relays are their own entity, separate from the PID controller. Where you are probably getting confused is that some of these devices have SSR "outputs", meaning you can program them to output a signal that works well with an SSR. The SSR output is what connects to the SSR itself.

Don't worry about all the tech in the wiki page below. All you need to know is what it does. An SSR is a switch that is controlled by an electric signal. In this case the PID generates the electric signal.

http://en.wikipedia.org/wiki/Solid-state_relay
 
brewman ! said:
Good. I don't want to be semi responsible for an accident.



Its a (slang) terminology thing. Solid State Relays are their own entity, separate from the PID controller. Where you are probably getting confused is that some of these devices have SSR "outputs", meaning you can program them to output a signal that works well with an SSR. The SSR output is what connects to the SSR itself.

Don't worry about all the tech in the wiki page below. All you need to know is what it does. An SSR is a switch that is controlled by an electric signal. In this case the PID generates the electric signal.

http://en.wikipedia.org/wiki/Solid-state_relay
Click to expand...

That is exactly the clarification I was looking for. Thanks so much!
 
Do they have the capability to accept a remote (analog) setpoint ? I come from the industrial world where most PIDs have this functionality. Cascading works better if the two PIDs communicate when they reach clamps or are taken out of cascade mode. The STC1000 has been repurposed to schedule fermentation setpoints. There maybe a variant that uses the two temperatures in a cascaded PID mode.
I like the building part of this hobby and may venture back into the embedded world into a BrewPI setup. I like the idea of open systems like the Allen Bradley where the systems are expandable, the user community is large, parts are of the shelf and reliable.
The cost per loop on the AB will be around $25
2 variable speed motors, 4 PIDS, 2 flow meters, 1 level controller
 
preinke said:
Do they have the capability to accept a remote (analog) setpoint ? I come from the industrial world where most PIDs have this functionality. Cascading works better if the two PIDs communicate when they reach clamps or are taken out of cascade mode. The STC1000 has been repurposed to schedule fermentation setpoints. There maybe a variant that uses the two temperatures in a cascaded PID mode.
I like the building part of this hobby and may venture back into the embedded world into a BrewPI setup. I like the idea of open systems like the Allen Bradley where the systems are expandable, the user community is large, parts are of the shelf and reliable.
The cost per loop on the AB will be around $25
2 variable speed motors, 4 PIDS, 2 flow meters, 1 level controller
Click to expand...

Here is the manual for one of the PID controllers that is commonly used.
http://mythopoeic.org/misc-files/JLD612_Manual.pdf

Do you see any inputs for a remote set point ?

So AB sells a $100 PLC, complete with 2 temperature inputs ?

Its great you have BrewPi aspirations. I don't think that fits with the KISS principle the OP is looking for. I'm building a steam powered brewery that overcomes all the RIMS scorching limitations. I didn't bring it up until now because it wasn't pertinent to this discussion.
 
I like to take my reading coming into the tube. I feel I need to know where it's at.... not where it's going. If wort coming into my tube is 152 then I'm guessing the rest is that temp.
 
Clankenbrew said:
I like to take my reading coming into the tube. I feel I need to know where it's at.... not where it's going. If wort coming into my tube is 152 then I'm guessing the rest is that temp.
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But if your inflow is at 148 and you're trying to reach 152 and you use that inflow temp to drive your element you may be heating wort much hotter than 152, in fact you might boil it before you start to see the temp increase on your inflow side.

It's fine to monitor temp in places other than immediately after the RIMS tube, but you should ALWAYS control your RIMS element based on the temp immediately after it. You can then decide if it needs to be set a little higher in order to get your actual mash temp where you want it.
 
The part that is still confusing me about my current setup is why the temp reads nearly 10 degrees warmer at the end of the return hose than directly over the element. Is it normal for the temp to rise that much in the 5 feet of hose after the RIMS tube or is my thermowell insulating the probe so it's reading lower than what is actually happening in the tube?

For what it's worth, I ordered new temp probes for my STC-1000. These are 1.5" stainless ends. Not sure if it will make a difference, but they look a lot nicer than the little, black piece of rubber.
 
So what do you do when your temp probes reading hot wort off the element and shuts off and the wort container is still low in temp? Your elements shutting off before your at temp.
I like my reading coming from the wort..
 
Clankenbrew said:
So what do you do when your temp probes reading hot wort off the element and shuts off and the wort container is still low in temp? Your elements shutting off before your at temp.
I like my reading coming from the wort..
Click to expand...

The controller running the RIMS loop should be running in SSR PWM mode and thus turning down the element power, not shutting it off.

There is also no reason for the element to be shutting down while the bed is cool unless the denaturing temp has been reached or the wort is being scorched. Since the denaturing temp is a lot higher than mash temps and scorching even higher than that, this should never be a real world problem.
 
Clankenbrew said:
So what do you do when your temp probes reading hot wort off the element and shuts off and the wort container is still low in temp? Your elements shutting off before your at temp.
I like my reading coming from the wort..
Click to expand...

You increase the set temp or duty cycle for the element until whatever temp it takes there gets you the desired temp in the mash. It's fine if your desired mash temp is 152 and you're reading higher than that coming off the element as long as you're not denaturing the enzymes. You run a MUCH higher risk of denaturing enzymes by controlling off the infeed temps, as well as having a system with tons of lag.
 
Im going to have to test and monitor with more probes inside the mash and adjust if necessary.
Im not convinced it makes a big difference as long as you have good flow rate.
 
augiedoggy said:
I thought this too but I had scorching issues when I forgot to turn on the pump or turned it off without killing the rims heat.... Now that I have spent the $20 total investment on the flow sensor and wiring components I have peace of mind that this will not happen again.
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Do you have a link to your $20 flow sensor?
 
Shred said:
The part that is still confusing me about my current setup is why the temp reads nearly 10 degrees warmer at the end of the return hose than directly over the element. Is it normal for the temp to rise that much in the 5 feet of hose after the RIMS tube or is my thermowell insulating the probe so it's reading lower than what is actually happening in the tube?

For what it's worth, I ordered new temp probes for my STC-1000. These are 1.5" stainless ends. Not sure if it will make a difference, but they look a lot nicer than the little, black piece of rubber.
Click to expand...

I have the same problem. It wouldn't be gaining 10 degrees in the hose. I'd expect it to lose a degree or two.

I manually check the temperature of the wort going back into the MLT and lower my PID temperature account for the difference. I could set the PID to account for the error, but after the mash I plug in a different probe, which it reads correctly, and use the panel to control my boil kettle.
 
I used to be of the mindset that the best place for the temp probe was at the RIMS outlet, I'm starting to reevaluate that position. If you are using a generic PID control (like most here use) then I still think it's the safest place.

I'm currently working on a custom RIMS controller using an Arduino. It really is eye opening to graph hard data on temp differences between the RIMS tube and the MLT. I don't feel the differences are insignificant.

Through some trial and error, and help from another forum member BigBlock, we're narrowing in on a cascade controller that uses the MLT output/RIMS input to control the temperature.

I'm using one temp probe at the RIMS output (becoming superfluous), one probe at the MLT ouput, and a cheap flow meter with pretty good results. Given liquid input temperature, flow rate, we can estimate the power required to heat the input to a given output temperature. We then use a simple PID routine to adjust the RIMS output setpoint. This way we can prevent scorching, denaturing AND know/control the temp of the actual MLT.

If folks are interested in the theory, code and development I can start a thread and link back here.
 
augiedoggy said:
I thought this too but I had scorching issues when I forgot to turn on the pump or turned it off without killing the rims heat.... Now that I have spent the $20 total investment on the flow sensor and wiring components I have peace of mind that this will not happen again.
Click to expand...

Agreed, as far as I'm concerned a flow switch/meter was required for my system. But in all fairness shouldn't your control panel be wired to cut power to the element if power to the pump is off?
 
Shred said:
The part that is still confusing me about my current setup is why the temp reads nearly 10 degrees warmer at the end of the return hose than directly over the element. Is it normal for the temp to rise that much in the 5 feet of hose after the RIMS tube or is my thermowell insulating the probe so it's reading lower than what is actually happening in the tube?

For what it's worth, I ordered new temp probes for my STC-1000. These are 1.5" stainless ends. Not sure if it will make a difference, but they look a lot nicer than the little, black piece of rubber.
Click to expand...

Are you using the STC's probe to measure both of these temperatures? If you'r measuring the output of the hose with a thermometer there may be calibration discrepancies. It could be that your thermowell is too large and your not getting a good transfer of heat to your probe. You could try some thermal paste or even some toothpaste (very temporary) between the probe and thermowell to try and see if that makes a difference.
 
thekraken said:
I used to be of the mindset that the best place for the temp probe was at the RIMS outlet, I'm starting to reevaluate that position. If you are using a generic PID control (like most here use) then I still think it's the safest place.

I'm currently working on a custom RIMS controller using an Arduino. It really is eye opening to graph hard data on temp differences between the RIMS tube and the MLT. I don't feel the differences are insignificant.

Through some trial and error, and help from another forum member BigBlock, we're narrowing in on a cascade controller that uses the MLT output/RIMS input to control the temperature.

I'm using one temp probe at the RIMS output, one probe at the MLT ouput (becoming superfluous), and a cheap flow meter with pretty good results. Given liquid input temperature, flow rate, we can estimate the power required to heat the input to a given output temperature. We then use a simple PID routine to adjust the RIMS output setpoint. This way we can prevent scorching, denaturing AND know/control the temp of the actual MLT.

If folks are interested in the theory, code and development I can start a thread and link back here.
Click to expand...

I am also going down the cascade route with variable MLT tuning based on flow rate with "clamped" RIMS output temperature setpoint based on MLT setpoint for stepped mash profiles. I am going the route with a Micr830 Allen Bradley but would be interested in your control structure and happy to share anything I am doing - mine is a work in progress. Please start another thread
 
thekraken said:
I'm currently working on a custom RIMS controller using an Arduino.

<snip>

If folks are interested in the theory, code and development I can start a thread and link back here.
Click to expand...

Please do.

If you write code, could you open source it ?

And could you make the control loop a generic self threaded library written in C or C++ with generic function calls like getMLTTemp() and getRIMSTemp(), so that it can be reused ?

I'm probably going to build a controller too, though I'll probably do mine on the RPi. Though Arduino isn't a bad choice either.
 
thekraken said:
Agreed, as far as I'm concerned a flow switch/meter was required for my system. But in all fairness shouldn't your control panel be wired to cut power to the element if power to the pump is off?
Click to expand...

Yeah thats one way of doing it but that wont help in a stuck sparge situation and that was one of my main concerns. plus my pumps are on pwm speed controllers so even if they are on the speed could inadvertently be set too low for proper flow arcoss the element and scorch.
 
I thought some of you may be interested in this plot. It's from some test data a recently collected, some of it may not make a lot of since because parts were in manual mode and parts were in auto mode but I think it does well to illustrate the possible temperature differences you could have between your MLT and RIMS tube. This was at 1gpm flow rate, the first half of the data was with a lid off the MLT, the second half of the data was with the lid on.

By the way, those of you that measure your flow what flow rates are you able to achieve in your mashes without sticking?

(edit: marked up the graph for clarity)
dN9I5Jv.png
 
Very interesting.

Are you sure the step to 155F didn't start at 6,000 seconds ?

How did the beer turn out ?
 
Tonight my local home brew club had a guest speaker speaking on mash chemistry. He was familiar with RIMS. He stated that the do not exceed temp for liquid out of the RIMS chamber was 75C or 167F.
 
brewman ! said:
Are you sure the step to 155F didn't start at 6,000 seconds ?
Click to expand...

Yep. Where ever the green line steps up indicates where the control was flipped to automatic control mode and the setpoint was stepped up.

How did the beer turn out ?
Click to expand...

This wasn't a brew, this was data collected while testing out tuning parameters for my controller.

brewman ! said:
Tonight my local home brew club had a guest speaker speaking on mash chemistry. He was familiar with RIMS. He stated that the do not exceed temp for liquid out of the RIMS chamber was 75C or 167F.
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167-170 is the generally stated temperature for mashout for any method because of an increased risk of tannin extraction as the temp goes beyond 170. Was the guest speaker just referring to this or did they have other reasons not to exceed 167?
 
thekraken said:
167-170 is the generally stated temperature for mashout for any method because of an increased risk of tannin extraction as the temp goes beyond 170. Was the guest speaker just referring to this or did they have other reasons not to exceed 167?
Click to expand...
He was a grad student studying brewing enzymes. His supervisor was at the back of the room watching his presentation. His reasoning was that 75C was the temperature at which significant irreversible damage to alpha and beta amylase enzymes occurs.
 
brewman ! said:
He was a grad student studying brewing enzymes. His supervisor was at the back of the room watching his presentation. His reasoning was that 75C was the temperature at which significant irreversible damage to alpha and beta amylase enzymes occurs.
Click to expand...

Maybe the speaker wasn't referring to mashout at that point, he was talking about during the normal mash period? If that's the case it threw me off a little bit because my little 120v RIMS tube is never going to exceed 167 during a ~150 mash. That's definitely something to consider if your controlling by the RIMS input with out a way to monitor the output and have slow flow rates or a high wattage element.

That's one of the reasons to mashout in the first place. You want to stop the enzymatic activity for "preserving your fermentable sugar profile".

http://www.howtobrew.com/section3/chapter17.html
 
I did some tasting over the last 4 days with 2 - 10gallon batches and found that when running my MYPIN TA4 @ 143 it will keep the mash right at 151 inside the cooler.

I'm not sure why the controller is not maintaining better temp at the temp it is set to.

The first batch I set and walked away, @ the 15 minutes remaining I stopped everything to add the 5.2Ph and took readings inside the tun and the mash was at 165 with the MYPIN set at 152. This may be a dumper!

I've got another test planned to swap the RTD to the wort inlet and take readings before it hits the element.

So far, taking readings @ exit is not recommended by me as it resulted in way too high of a mash temp inside the cooler.
 
Sounds like you Pid isn't maintaining setpoint or you're not getting a true exit temp. If the temps are reading correctly you prob want to re-tune. Fundamentally your mash temp should always be less than your rims discharge while heating/maintaining temp.

Couple of things to try if you haven't already....

back check your discharge temps
Check calibration on all sensors/thermometers
make sure you have good conduction in your thermowell (thermal paste)if you have one.
 
Clankenbrew said:
I did some tasting over the last 4 days with 2 - 10gallon batches and found that when running my MYPIN TA4 @ 143 it will keep the mash right at 151 inside the cooler.

I'm not sure why the controller is not maintaining better temp at the temp it is set to.

The first batch I set and walked away, @ the 15 minutes remaining I stopped everything to add the 5.2Ph and took readings inside the tun and the mash was at 165 with the MYPIN set at 152. This may be a dumper!

I've got another test planned to swap the RTD to the wort inlet and take readings before it hits the element.

So far, taking readings @ exit is not recommended by me as it resulted in way too high of a mash temp inside the cooler.
Click to expand...
change the "I" setting in your mypin pid to "1" so it stops overshooting... I had to do the same thing to all my mypins....
 
Clankenbrew said:
I did some tasting over the last 4 days with 2 - 10gallon batches and found that when running my MYPIN TA4 @ 143 it will keep the mash right at 151 inside the cooler.

I'm not sure why the controller is not maintaining better temp at the temp it is set to.

The first batch I set and walked away, @ the 15 minutes remaining I stopped everything to add the 5.2Ph and took readings inside the tun and the mash was at 165 with the MYPIN set at 152. This may be a dumper!

I've got another test planned to swap the RTD to the wort inlet and take readings before it hits the element.

So far, taking readings @ exit is not recommended by me as it resulted in way too high of a mash temp inside the cooler.
Click to expand...

Are you measuring your temp at the exit of the mash tun or at the RIMS tube exit? I believe the general consensus is to measure temps at the exit of the RIMS tube.
 
stlbeer said:
Are you measuring your temp at the exit of the mash tun or at the RIMS tube exit? I believe the general consensus is to measure temps at the exit of the RIMS tube.
Click to expand...

I somehow missed his comment indicating what hes doing... Hes likely adjusting at the "wort outlet" of his mashtun which would account for the major overshooting too since the whole time the mash is climbing in temp from the top down the rims sensor below is still reading low and telling the rims to stay on and heat so more..
Hence the whole point of this discussion and the fact that the rims outlet is the BEST and most accurate place to get a real time temp flow reading. So if he read the thread he would see what his problem is...
 
Clankenbrew said:
Rtd probe shown at top of RIMS.
Click to expand...

Is your probe reaching the wort?

Did you calibrate the temperature on your controller?

My RIMS tube is horizontal instead of vertical. I don't know that that makes a difference, except that there won't be air bubble accumulation in the tube if you have it horizontal with the outlet pointed up.
 
The reason its vertical is because when I ran it horizontal It dry fired an element and burnt out. With the element at the bottom its always in wort.
I never calibrated the RTD to the PID.. Can this be done with a MYPIN TA4?
 
Clankenbrew said:
The reason its vertical is because when I ran it horizontal It dry fired an element and burnt out. With the element at the bottom its always in wort.
I never calibrated the RTD to the PID.. Can this be done with a MYPIN TA4?
Click to expand...

did you shange the "i" setting to 1? calibrating and autotuning wont help if you havent done this... the default setting cause overshooting on the mypins when used for this for some reason.
Also as mentioned the way your setup is the probe is likely sitting in a trapped air pocket... the lliquid should exit at the highest point and the rims shoul be positioned so as the liquid comes in all the air is pushed out without being trapped.
 
The RIMS tube in my setup is midway to the lowest point. Top to bottom is mash tun, pump (lowest point), RIMS tube, then back to mash tun. With the RIMS tube lower than the top level of the mash tun it should never be empty.

To prevent a dry fire (and it may have already been stated in this thread) you should have the pump and PID control circuit on the same switch (different sides of the same DPST switch). This way the element can't fire unless the pump is running. Or if the SSR has failed closed - but you'll notice this pretty quickly.

 
I dont think it matters much myself how high or low your rims is positioned since as mentioned it should only be on when the pump is pumping wort through it... It does however matter how the inlets and outlets are orientated since this can cause air pockets to get trapped inside the rims tube and cause devastating effects.
 

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