2 RTD Temp Sensors (Switched) and 1 PID Controller

[resslerk]

I did do some searching and couldn't find an answer... although I'm sure it is out there hiding! So if I'm missing it and you know where it is, please post the link.

I'd like to add a 2nd RTD sensor to my system into Mash Tun. I already have one in my Boil Kettle and have a Auber PID controller. Essentially while mashing I want to be able to flip a switch and activate one sensor versus the other. What is the best way to do this? What would the wiring for the two RTD's tied to the switch look like?

 

[Reelale]

Just spit-ballin here, but couldn't you hook both sensors up to the same terminal on the PID and route one line from each to a DPDT switch? In other words, the switch in one postion would activate one sensor, and the switch in the other position would activate the other. Middle postition would be off for both sensors.

 

[SweetSounds]

That's what I plan to do as well.
I haven't heard of anyone trying it yet, but I don't know why it wouldn't work!

If you give this a shot I'd love to know how it works for you!

My plan:

 

[lamarguy]

You could certainly switch sensor inputs using a DPDT switch or relay but your PID will only have P, I, and D parameters to control one process (e.g., mash tun or boil tun).

For example, the PID parameters for a boil are set to achieve maximum temperature increase in the shortest amount of time. A mash process is very different.

 

[bmckee56]

Auber sells panel mounted quick disconnects. Why not use the disconnect and simply plug which ever RTD you want to use into it.

Here is a link: http://www.auberins.com/index.php?main_page=product_info&cPath=7&products_id=118

Here is a picture of it:

Can't get much easier than that right? I use "K" type sensors and use the panel mounted connectors for them. I use my PID controller for my Electric Smoker and my HLT.

Salute!

 

[Sawdustguy]

Just keep in mind that if you are using the PID to control a process like a RIMS and switch the sensor the process is no longer under control.

 

[Walker]

The question is: what is the purpose of the RTD in the kettle? If it's just for monitoring the temp of the wort as you chill, then you can put a switch (you have to switch ALL of the wires) or use the connectors and swap cables. The PID is just a thermometer display at this point, and there is no process being controlled (just monitored).

 

[Mose]

This is waht I'm planning on doing. One to control the boil and heating strike water, since I am going two vessle, and the other at the output of the HERMS coil during the mash.

I haven't set it up and tried to program anything but I see guys asking alot about programing the PID and tuning it, will switching between two identical RTD's in different locations effect the tuning? My PID isn't even out of the box yet so I'm way ahead of myself here.

Auber sells panel mounted quick disconnects. Why not use the disconnect and simply plug which ever RTD you want to use into it.

Here is a link: http://www.auberins.com/index.php?main_page=product_info&cPath=7&products_id=118

Here is a picture of it:

Can't get much easier than that right? I use "K" type sensors and use the panel mounted connectors for them. I use my PID controller for my Electric Smoker and my HLT.

Salute!

 

[Walker]

This is waht I'm planning on doing. One to control the boil and heating strike water, since I am going two vessle, and the other at the output of the HERMS coil during the mash.

If you are using a PID with manual mode to control your boil strength, then it doesn't even need a temp probe in the kettle.

Manual mode means you set a duty cycle up manually. You tell it to be on a percentage of the time over a period of time. (like, 80% on over the course of 1 second).

The temp probe is not used in this mode.

 

[Mose]

If you are using a PID with manual mode to control your boil strength, then it doesn't even need a temp probe in the kettle.

Manual mode means you set a duty cycle up manually. You tell it to be on a percentage of the time over a period of time. (like, 80% on over the course of 1 second).

The temp probe is not used in this mode.

Right, My BK RTD will be used for heating strike water and recirc water since I won't have a traditional HLT. I added the RTD to the HERMS output after reading one of your posts on the subject of proper mash temp control and where to take the reading, since the heat exchange with the HERMS coil won't be 100%. With the two vessel set up the HERMS will be in the BK and will also serve as the IC post boil. That is if I ever drill a hole and cut a top.

 

[Walker]

Right, My BK RTD will be used for heating strike water and recirc water since I won't have a traditional HLT. I added the RTD to the HERMS output after reading one of your posts on the subject of proper mash temp control and where to take the reading, since the heat exchange with the HERMS coil won't be 100%. With the two vessel set up the HERMS will be in the BK and will also serve as the IC post boil. That is if I ever drill a hole and cut a top.

Ah... if you are doing it like I do, then you can still avoid a probe in the kettle. The only one I have is the one on the HERMS coil.

When I am heating up water to start the day, I put the coil in the kettle, and pump the kettle's water through the coil and right back into itself. This lets me use the probe on the coil output to monitor and control the temp of the water as I heat it up.

 

[Mose]

AH....Genius...That solves any tuning issues, if they exist at all, and certainly simplifies the wires running all over the rig. Looks like I bought 1 to many RTDs.

Sorry for the Thread Jack OP. Back to you, it's not all about me.

Ah... if you are doing it like I do, then you can still avoid a probe in the kettle. The only one I have is the one on the HERMS coil.

When I am heating up water to start the day, I put the coil in the kettle, and pump the kettle's water through the coil and right back into itself. This lets me use the probe on the coil output to monitor and control the temp of the water as I heat it up.