PID Recommendations?

[Camo6]

Ramp/soak are actual functions in some controller units. These aren't needed for a HERMS system to reach or maintain a set temp.

PID = proportional, integral, derivitive, which are factors put in the Laplace transform of the transfer function blah blah >>> all PID means for our intent and purpose is that there are 'smarts' in the controller which incorporate a feedback loop to acheive a set value. i.e you want 62°C at a certain point, then the controller with achieve 62°C at that point and maintain it (regardless of where the system is being heated or cooled).

Ramp (as a function) maintains or limits the rate of change of a value. You can adjust the ramp so you can limit the rate of heating to 0.5°C/min. Alternatively, you can set it to 1.5°C/min when your system can only do 1°C/min, in which case it will be like switching it into manual. In the absence of ramp the controller will simply heat using PID.

Soak (as a function) maintains a set value (utilising PID control) for a given amount of time before moving to another value. This is handy for step mashing in the home brew scene, where you could have a soak at 65, 72 then 78 for example.

In my brewery I turn my PID to 58°C for mash-in. The PID unit will keep the element going until it hits about 51°C, then start cycling the HERMS element off. This slows down the heating considerably as it learns from the feedback loop, and can take about 4 mins to get from 57-58°C. However, by doing this it avoids overshoot and will sit on 58°C for hours on end, which is the whole point of PID.

In reality, I walk away, and come back an hour later and the MT is at 58°C. I change each step manually and have a timer on my phone for the steps, so I don't have a need for extra stuff. To each their own though.

Soooo, in short, ramp is to reach a temp and soak is to maintain a temp.

You wouldn't be an engineer by any chance would you Wiggman?

 

[sponge]

Lets leave the engineers out of this

h34r:

 

[TheWiggman]

Soooo, in short, ramp is to reach a temp and soak is to maintain a temp.

... no (kinda). You don't need 'ramp' to reach a temp, you don't need 'soak' to maintain a temp.
BUT
Ramp (as a function) will reach a temp at a specific rate
Soak (as a function) will maintain a tamp for a set amount of time

You wouldn't be an engineer by any chance would you Wiggman?

I'm just your regular internet forum troll

 

[mattlea266]

I use 2 SESTOS PIDs, no ramp/soak function, in my system and they work fine at raising and holding temperature. I did lash out on these http://www.auberins.com/index.php?main_page=product_info&cPath=20_15&products_id=249 probes and got them from AUBERINS, they are fantastic. Got the braid upgrade a well. Really fast temp readings. I did have a cheap ebay probe for testing and found it miles behind the AUBERINS probes.

So far I have not regretted buying the cheap PIDs and at $30 each it's no big deal if one fails.

 

[Adam Howard]

I don't know why everyone's getting over-analytical about the whole ramp/soak thing. The only thing to note about the difference between the two (non ramp/soak and ramp soak) is that one model will get to and hold a temperature but do nothing more without playing with it and the ramp/soak one can be programmed with steps. For HERMS it's a no brainer, you go a ramp/soak PID so that you can program in your whole mash schedule just like a Braumeister and then walk away and do the mowing to come back for the sparge.

I hope Mick has been able to make heads and tails out of it all.

 

[_Mick_]

Wow... Thanks for all the info guys. Pretty sure ive made sence of it.

Anyways, by what has been said verses the recipes I make, Ill just go with the non ramp/soak PID. For staters Ill just using it for the HLT and when I go down the HERMS road the standard PID will do too since I only do a sacc rest and a mashout which I guess I can put in manually.

Now as far as brands go, is there really much difference between the sestos and Auber? Also Ive seen some detachable/braided pt100 probe+cables on ebay for about $25, can anyone comment on those?

Thanks again for the help!

Cheers

 

[fraser_john]

<snip>
Ramp (as a function) will reach a temp at a specific rate
<snip>

Yes! IFF your system can heat at the specific rate required. No point have a ramp of 70c-77c over 5 minutes if your system can only heat at 1c/min.

The good thing about the Auberins ramp/soak is that if you set a too aggressive time frame in which to ramp, the next step just waits till the temp is reached to start its step timer. Great units if ramp/soak and multi steps is what you need.

Personally I find a 62c through 65c for 30 minutes is a great well balanced wort for nearly all ales, I just vary the amount of crystal to change the sweetness of the final product.

 

[squirt in the turns]

Anyways, by what has been said verses the recipes I make, Ill just go with the non ramp/soak PID. For staters Ill just using it for the HLT and when I go down the HERMS road the standard PID will do too since I only do a sacc rest and a mashout which I guess I can put in manually.

Once you've built your HERMS and have the ability to do step mashes, you will find yourself wanting to do step mashes. I bought the Sestos PID (as far as I know, Sestos don't make a ramp/soak model) and wish I'd gone for the Auberins with the ramp/soak. Of course you can do step mashes without ramp/soak, but wouldn't you rather be mowing the lawn (apparently this is the AHB-approved inter-mash activity) than returning multiple times to fiddle with the PID?

To reiterate what others have said, you could forgo the whole PID thing for the HLT - I've always found an STC-1000 to be accurate enough, especially with the fine control you'll get with a HERMS.

 

[_Mick_]

To reiterate what others have said, you could forgo the whole PID thing for the HLT - I've always found an STC-1000 to be accurate enough, especially with the fine control you'll get with a HERMS.

Good point, I guess if its just for my HLT an STC should do the trick. Thoughts anyone?

 

[Camo6]

I ran an STC for both HLT and HERMS. Both worked flawlessly with little overshoot. More than suitable for a HLT.

 

[_Mick_]

Cheers Camo, might just do that for the hlt.