I2C connected PID controller?

[cowger]

Hi, I'm trying to find a temperature controller for my RIMS setup that I can remotely control (say, with an Arduino).

Before I go any farther, I would think that this is a question that has been asked/answered a 100 times, and, if so, I really hate to be one of those guys, but I've spent an hour now searching this forum and haven't found anything beyond a handful of RS-485 connected controllers.

Ideally, I'd like to use a simpler connection, like I2C, SPI, or even a TTL-level serial input. Does anything like this exist?

I know that many just bypass the controller and run their own PID firmware to make this happen, but I was thinking that if something is easily available that I could replace my "MyPin" PID controller with, it would be a quick and simple upgrade to my setup.

All I really want to do for now is to just be able to run a stepped profile for the mash temp.

Thanks for any pointers.
Bryan
Auburn, CA

 

[JoshuaW]

If you are looking for simple and remote control, I would use a BCS-460.

 

[crane]

You can do a stepped mash with the automation direct solo PIDs. Some of them have rs-485 interfaces that allow you to run their configuration software on a PC. It gives you a nice table that you can enter the times/Temps into so you don't have to spend a ton of time pressing buttons on the PID itself. You can setup the profile ahead of time so you don't need to have a PC connected while brewing.

Also I am sure adafruit, spark fun, or some other hobby electronics place sells a UART to RS-485 breakout board. In general RS-485 is way more robust of an interface when your signals leave the circuit board. I2C and SPI aren't really meant for cables or long runs.

 

[thekraken]

Why don't you just use an Arduino?

 

[cowger]

Also I am sure adafruit, spark fun, or some other hobby electronics place sells a UART to RS-485 breakout board. In general RS-485 is way more robust of an interface when your signals leave the circuit board. I2C and SPI aren't really meant for cables or long runs.

Thanks, I think this is the way to go. I found an older thread in which New England Temperature Sensors were selling a very nice RS-232 controller for $75, so I picked one of those up. And I agree, a simple Arduino RS-232 shield solves that problem.

Bryan

 

[BigBlock]

I have an arduino talking modbus RTU (rs485) to an automation direct Plc (sending and recieving) If you're interested I can send you the source code. All you would likely need to do is update the communication settings and signal address's.

 

[cowger]

Why don't you just use an Arduino?

I don't have a great answer, other than I was just looking for something quick and easy. I'm very comfortable with the Arduino programming environment but wasn't sure how to replace a PID controller in terms of both hardware and firmware.

With the new PID controller on its way, I'm thinking I can just write a quick sketch to implement one or more mash temp profiles (e.g. 30 minute rest at 140, ramp up by 1 degree each 3 minutes to 158, mash out at 170, etc). Add a little LCD display and a couple of control buttons and I'm done. We'll see....

 

[cowger]

I have an arduino talking modbus RTU (rs485) to an automation direct Plc (sending and recieving) If you're interested I can send you the source code. All you would likely need to do is update the communication settings and signal address's.

Yes, please! PM sent...

 

[santacruzbob]

Sounds like you've probably already got the load switching portion of the problem handled. I would stick with a software approach as it'll be much easier to tune than a black box solution.

-Bob
(also in Auburn, CA)

 

[cowger]

Sounds like you've probably already got the load switching portion of the problem handled. I would stick with a software approach as it'll be much easier to tune than a black box solution.

-Bob
(also in Auburn, CA)

Hi Bob,

Yes, I have a solid state relay that's switching a 220V element in my RIMS, with a temperature probe into my current PID controller, creating the closed-loop system. While I know many have done it, I didn't necessarily want to reinvent the wheel with hardware to interface to the temperature probe / SSR, and the software to do the fuzzy logic / auto-tune.

I may well get there someday, but I'm hoping I'll be fine with an upgraded PID controller for now. As I mentioned, I simply wish to auto-step my mash profile. I should have that hardware in this week and will play around with the programming aspect before converting my brew rig over.

Bryan