PID Function

So, As it were. I can hook up a PID and even get it to work properly, but can you get them to run on set time intervals for a set temp? I realize that this could equipment dependent. I am looking for some feed back, so let me know if i am asking to much or am I on track and I just need guidance. Thanks!

Possibly. It depends on the device you are using. What have you got?

Advanced temperature controllers have programmable ramp and soak times.

wihophead said:

Advanced temperature controllers have programmable ramp and soak times.

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Well, those are not functions on my PID. No big deal though. I can use it for my boil kettle. So with that said, any suggestions on on a reliable PID with the required functions? S.

Here we use Honeywell Temperature controllers with the set point program and adaptive tune option but you would be looking at hundreds of dollars for one of those.

We also use Watlow controllers but none with the ramp and soak option but I did find a model that has it and would probably work for you but it is pricey.

http://www.instrumart.com/Product.aspx?ProductID=20322

I would suggest looking at off brands and see if they offer the same features...I will keep an eye open for you.

Good luck

wihophead said:

We also use Watlow controllers but none with the ramp and soak option but I did find a model that has it and would probably work for you but it is pricey.

http://www.instrumart.com/Product.aspx?ProductID=20322

I would suggest looking at off brands and see if they offer the same features...I will keep an eye open for you.

Good luck

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Say, Thank you again. I will take all the help I can get.

Looks like I could get a PID from automation direct for under a 100 bucks with near limitless ramp soak control. Not really, but more than any brewer really needs. One question though, is It has just PID, manual, and (ramp and soak) features. It does not seem to have the other features commonly found on other Temp controllers. Do I need those other features? What is the Norm? S.

That sounds like that is just what you need, then you just have to choose the type of output you will need.

All this and a box of rocks just to get to multistep mashing. I am certain I will go with a relay output and connect to a ssr and then ajust the relay controll intervals on the PID. I can then connect a magnetic two pole switch in line to kill the power to element in an outage if I am not in the room, along with some other nice safety features... Who knows some day I might even automate it with a PLC. I don't think I will get that board though. Truth be told though I have a SLC 500 sitting in my garage awaiting something to do. It would be certain overkill for a brewing set up, but the price is right. Any who's Thanks for the input wihophead, I am great-full for your guidance once again. S.

slnies said:

Who knows some day I might even automate it with a PLC. I don't think I will get that board though. Truth be told though I have a SLC 500 sitting in my garage awaiting something to do. It would be certain overkill for a brewing set up, but the price is right.

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There is no such thing as overkill..LOL

Unfortunately I don't work with A-B anymore but I still have a SLC500 fixed IO and a couple SLC500 output cards in the basement along with RSLogix 500 discs.

I work strictly with GE PLCs now for the most part. I have a 90-30 and a Quickpanel that I am dieing to put to use once I get into all grain. The 90-30 has a built in PID function block but I think you must use it with an analog output which creates new challenges.

wihophead said:

There is no such thing as overkill..LOL

Unfortunately I don't work with A-B anymore but I still have a SLC500 fixed IO and a couple SLC500 output cards in the basement along with RSLogix 500 discs.

I work strictly with GE PLCs now for the most part. I have a 90-30 and a Quickpanel that I am dieing to put to use once I get into all grain. The 90-30 has a built in PID function block but I think you must use it with an analog output which creates new challenges.

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That sounds like quit a cool challenge. You are going to have to tell me how that goes. That automation direct pid I am looking at I can get with a comm port, and I think i could hook it up on a net a with direct logic plc. I am Not quit sure yet, but i am looking into it. It just so happens you can pick up a direct logic PLC along with the I/O modules on ebay for 40 to 60 bucks. Interesting eah. Well I have to go back to enjoying christmas with the rest of the family. s

Finding and purchasing the PLC hardware is the easy part, finding the inexpensive proportional control valves and sensors is the difficult part. Have been building a sytem around opto 22 hardware for a steam rims system, currently in the hardware testing and calibration stage with software under development. Needed a system that would take care of the tedious part of watching flows and temperatures with flame safety controls for the burners so there would be time to do the other things necessary.

kladue said:

Finding and purchasing the PLC hardware is the easy part, finding the inexpensive proportional control valves and sensors is the difficult part. Have been building a sytem around opto 22 hardware for a steam rims system, currently in the hardware testing and calibration stage with software under development. Needed a system that would take care of the tedious part of watching flows and temperatures with flame safety controls for the burners so there would be time to do the other things necessary.

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That is why I said it creates a new set of challenges....LOL

But I think I found a way to write a set of instructions that would convert my PID analog signal to a time based discrete output so I can use the built in PLC PID function with a SSR to power a valve or heater element.

This way I can get away from having to use a proportional valve or SCR drive even though that would be best way to go.

For flame safety are you going to sense temperature or go all out and use a UV flame detector?

wihophead said:

That is why I said it creates a new set of challenges....LOL

But I think I found a way to write a set of instructions that would convert my PID analog signal to a time based discrete output so I can use the built in PLC PID function with a SSR to power a valve or heater element.

This way I can get away from having to use a proportional valve or SCR drive even though that would be best way to go.

For flame safety are you going to sense temperature or go all out and use a UV flame detector?

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There is an answer for that, I have a buddy that is in a HVAC guy. We were talking about such a device the other day. It actually senses gas flow and heat so that if ignition fails or the flame is arrested the valve shuts off the gas. I will talk to him some time this week and post that actual devise name and what it really does in more detail.

I am also interested in analog signal conversion, that sound like a spiffy bit of programing if it works. S.

Flame safety is provided by the Honeywell S87D direct spark ignition module and the Honeywell Q179C pilot burner with ignition and flame sensing rods. Command from PLC powers ignition module which opens fuel solenoid valve and lights pilot, if pilot does not light in 6 seconds or if it flames out it closes the fuel solenoid valve. Burner fuel flow is controlled by a 0-5V signal to the mass flow controller which changes the flow of propane to the burner.

That a good idea, I never thought about using parts from a HVAC unit. I will have to do some talking with the HVAC guys at work. I am familiar with Honeywell proportional gas valves and UV flame sensors we used to use on melting furnaces but the cost of them would keep them out of reach for most people.

The idea to convert an analog signal goes like this...
The PID function outputs a signal of 0-32767 so I will convert that to a percentage.
So say you use a time base of 10 seconds in order to drive at 50% you would turn the heat on for 5 seconds off for 5 seconds like wise if you want to drive at 90% you would turn on for 9 seconds off for 1 second.
I spoke with the "vacuum furnace guy" at work and he has used this method with great success on furnace upgrades when the company didn't want spend money on a variable Saturable reactor.

Thanks for the idea...

Look on Ebay for the direct spark ignition modules, try for the ones with single rod system where ignition and flame sense are combined. As for an analog voltage out from a digital output you could use a resistor- capacitior combination to get a voltage output that is proportional to pulse width output of controller.

To get an analog signal I would simply use an analog card.
I was referring to using an analog output of a PDI function block from a 90-30 PLC which actually outputs a 0-32767 register value then taking that value and creating a time based discrete output to create a proportional output. But if I find a cost effective proportional solution like you mentioned I would simply use an analog card as I stated.

When you torment the HVAC guys have them look for Belimo or Johnson control low voltage actuated ball valves with a 2-10V control signal. The Belimo valves show up on Ebay regularly at resonable prices, valves are stainless, actuators 24V AC/DC. Make sure the actuator is a LR series with proportional control and not the TR series with 2 position or floating control.

slnies said:

T It just so happens you can pick up a direct logic PLC along with the I/O modules on ebay for 40 to 60 bucks.

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I got all excited when I read that and went to Ebay to buy my new PLC. I guess that price is for the American website because it's considerably more on the Canadian one.

I haven't used the direct logic PLC's at all. What is it about them that make them so cheap?

They really are not all that cheap, what makes them affordable for most people is the software. They actually got there start in PLCs when they bought the rights to our Series 1 PLC. GE doesn't support them anymore so we actually have to use their software and there is only one guy at work that actually uses it. JFYI 1 GE Machine Addition license costs around $5000, I have no idea what a RSLogix license costs anymore.

Luckily I have a Machine Addition license and an old RSLogix license...

kladue said:

When you torment the HVAC guys have them look for Belimo or Johnson control low voltage actuated ball valves with a 2-10V control signal. The Belimo valves show up on Ebay regularly at resonable prices, valves are stainless, actuators 24V AC/DC. Make sure the actuator is a LR series with proportional control and not the TR series with 2 position or floating control.

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I use the Johnson Control valves you mentioned for controlling X-Ray tube temperature during seasoning. Trust me I always keep my eyes open, it is unbelievable what they throw away.....

Are you going to use RTD's or thermocouples for temperature sensors or try to make your own solid state device sensors. I have kept with industry standard devices so that simulators and calibration equipment that I use will work to calibrate the equipment. Currently in the hardware testing phase with the water and boiler control panel and devices utilizing a utility program from Opto 22.

Fingers said:

I got all excited when I read that and went to Ebay to buy my new PLC. I guess that price is for the American website because it's considerably more on the Canadian one.

I haven't used the direct logic PLC's at all. What is it about them that make them so cheap?

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The gentlemen responsible for starting the company in the first place wanted to undercut the big boys, he also wanted to make the plc a smaller unit. He succeeded at both. Even Brand spanky a koyo or direct logic controller is less than half the price of its competitors. How ever because you pay less you also don't get all of the goodies that come as standard programming on the AB, GE(Funuc), Siemens, or schneider products. I get to work with a good number of them and I can tell you straight up that you get what you pay for. That is not to say that they are bad. They are very reliable. They are just not all that user friendly. This of course is my opinion, I like AB because that is what I learned on, and it is easy. Not really, but you get the point. It is possible to grab any of the brands on ebay in that price range if you take your time and limit your pocket. I won a AB SLC CPU, and two I/O boards two months ago for 75$ including a 10 slot frame for GE 90-30. It was a good deal and it works great. I looked though, for three months prior. Persistence always pays. I also work with them, so every once in a while I get one to take home after an update. S.

kladue said:

Are you going to use RTD's or thermocouples for temperature sensors or try to make your own solid state device sensors. I have kept with industry standard devices so that simulators and calibration equipment that I use will work to calibrate the equipment. Currently in the hardware testing phase with the water and boiler control panel and devices utilizing a utility program from Opto 22.

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Is it going well so fare?

kladue said:

Are you going to use RTD's or thermocouples for temperature sensors or try to make your own solid state device sensors. I have kept with industry standard devices so that simulators and calibration equipment that I use will work to calibrate the equipment. Currently in the hardware testing phase with the water and boiler control panel and devices utilizing a utility program from Opto 22.

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We use OPTO22 here on our functional test cells but I have never had the opportunity to work with the software, they seem pretty reliable.

I have these at my disposal
http://www.sensortecinc.com/docs/catalog/4_mgo.pdf
I have the type "MGO" with the snap and screw covers and a Q2 4-20mA transmitter with a temperature range of 0-220°F
With these I can feed the output directly into a 4-20mA analog input card since I haven't got my hands on a thermocouple card yet.

slnies said:

I won a AB 90-30 CPU, and two I/O boards two months ago for 75$ including a 10 slot frame. It was a good deal and it works great. I looked though, for three months prior. Persistence always pays. I also work with them, so every once in a while I get one to take home after an update. S.

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A 90-30 is a GE Fanuc PLC not AB, a comparable AB would be a SLC 500. If it is in fact a SLC 500 I have a couple cards....I think they might be 16pt output cards I can't remember but if you are interested I can take a look, they are brand new in the box. If it was a GE Fanuc what CPU was it...331, 341 etc...

Panel wiring and checkout is finished, serial to ethernet communications interface working, boiler ignition and flame safety along with gas flow control to burner working. Next up is connecting water tank and testing level transmitter, fill valve, pump, water flow control for boiler, and glycol coolant valve. Here is a picture of the system schematic and panel, http:///picasaweb.google.com/kevin.ladue/Phase2Brewery/photo#5030791467733206146 here is a picture of the control hardware on the aluminum panels http://picasaweb.google.com/kevin.ladue/Phase2BrewingPanel/photo#5144799706307697042

That is looking great....those look to be the exact valves we use for temperature control but I don't see the controls for them. Are those panels hinged on the strut???

The valves are Belimo with 2-10VDC control input, and the panels are hinged on this temporary testing stand. Next up is the right hand panel with the wort pumping and steam mixer components. Need to finish welding the kettle burner, counterflow chiller, and support brackets for mash and boil kettles.

Yes those are the same valves we use in conjunction with a Johnson Controls A350P Proportional Temperature Control

A 90-30 is a GE Fanuc PLC not AB, a comparable AB would be a SLC 500. If it is in fact a SLC 500 I have a couple cards....I think they might be 16pt output cards I can't remember but if you are interested I can take a look, they are brand new in the box. If it was a GE Fanuc what CPU was it...331, 341 etc...[/QUOTE]
You are correct. I have an SLC 500, but I also have the powersupply and rack for the 90-30. I get so excited about this stuff, I forget to add the details. Sorry. S

kladue said:

Panel wiring and checkout is finished, serial to ethernet communications interface working, boiler ignition and flame safety along with gas flow control to burner working. Next up is connecting water tank and testing level transmitter, fill valve, pump, water flow control for boiler, and glycol coolant valve. Here is a picture of the system schematic and panel, http:///picasaweb.google.com/kevin.ladue/Phase2Brewery/photo#5030791467733206146 here is a picture of the control hardware on the aluminum panels http://picasaweb.google.com/kevin.ladue/Phase2BrewingPanel/photo#5144799706307697042

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OK, So that is deffinitivly brew porn. Well done. S.

Ignition and burner fuel flow systems testing completed, water pumping and boiler operation for strike, sparge, and steam production testing is next. Last step is to start working on the operating software as the Opto G1 hardware is strictly I/O without built in control functions as found in other more modern PLC systems. New brewshop was built and needs plumbing, wiring, exhaust hood, and exhaust fan installed before moving brewing hardware from garage to permanent installation.