PID control temperature of oven

Hi! I should check the temperature of an oven through a PID control.
I wish that, after setting the reference temperature, the system acts on the power supply and change the current on the resistances of the oven, so that the temperature of the oven reaches the reference temperature.
Not knowing the programming language labview, I wanted to know if any of you have already saved the program in the PC and can post it, please.
Thank You!

aputman wrote:
That's why I used words like "think" and "may". I haven't been successful at it but I am definitely no expert.
What sort of incorrect response do you get from the heater system? If you're actively working on such a project I'd be happy to help.
For tuning a slow system, I highly recommend starting with the Cohen-Coon method (or the similar Ziegler-Nichols Open Loop approach). Take the PID out of the loop. Set the output at a fixed level and allow the system to stabilize. Change the output, and allow the system to stabilize again (make sure you wait until the system is actually stable). Record the output and process variable the entire time. Then you use that data to make a couple of quick measurements, plug the numbers into the tuning formula, and you get your gains. Unless the system is horribly non-linear, these gains will work well. Make sure you get all the units correct (for example, the LabVIEW PID block expects Integral Time in minutes, and not an integral gain).

Similar Messages

I need to maintain a temperature profile for my process.Can i use PID control for this application?

Hi all,
I need to maintain a temperature for my process.Can i use PID control vi's for this application?
I have NI-PCI 6023E DAQ board.Should I need any other hardware components???
Any help in this regard is highly appreciated.
Thanks,
radhika

Hi,
Thanks for your reply.
I do have a temperature sensor and it is read by the DAQ (NI 6023E) .
Also i have a voltage input to the program which has to be controlled in order to control the temperature.
So , I am using a PID , the output of the PID should control the Voltage input so that the temperature is controlled.
Can I give the voltage input and the temperature to the PID through the DAQ and just use one more channel in the DAQ to get the output from the PID.Will that work???
I am not sure why you have mentioned SC2345,SCB68.
Thanks,
radhika

PID control in a windows CE Labview application

Hi there,
I want to build an application that will control the temperature in some ovens, using PID control. The application will be running in a controller (or a touch panel computer) with windows CE OS. I have Labview 8.6, PID control toolkit 8.6 and Touch panel module 8.6. The problem is that the PID vi's don't seem to work in touch panel module.
Is there any way to implement PID control in a windows CE Labview application?
Thanks in advance.
Solved!
Go to Solution.

I think with a timed loop you can run reasonable good timing down to 1 mSecond. I think 1 mSecond is the lower limit for non realtime systems like Windows/windows CE. And if you have the PID toolkit this will supply you with the functions you need. You do not need an extra CE PID toolkit. This because the touch panel module run under your standard Labview environment. But I do not know if all the functions in the PID tool like fuzzy logic are compatible with CE. Have you also considered Windows Embedded as OS for your module. With windows Embedded you can run standard Labview built exe files
Both Windows Embedded, and XP Embedded can be trailed
http://www.microsoft.com/windowsembedded/en-us/products/westandard/default.mspx
Besides which, my opinion is that Express VIs Carthage must be destroyed deleted
(Sorry no Labview "brag list" so far)

Looking for a reasonable looptime for my PID controler!!

Good morning!
I am trying to do a PID control of a combustionchamber. The setpoint and process value are the output temperature, the value to operate is the massstream of the fuel. My in- and output datas are refreshed every 50 ms. My problem is...
What is a reasonable looptime for my PID control?
Do you have any ideas???
thanks RT

My group has used the Sun Electronics PC-1000 Process Controller for some time, with good results. There are some instructions in the beginning of this Engineering Note (pdf link) that discribe how to iteratively determine the PID coefficients for a linear system. I'm not a mathematician, so I can't vouch for whole document, but their somewhat antiquated instruments DO work
Now is the right time to use %^<%Y-%m-%dT%H:%M:%S%3uZ>T
If you don't hate time zones, you're not a real programmer.
"You are what you don't automate"
Inplaceness is synonymous with insidiousness

Can anyone help with a PID control vi

Hi
I am doing a project at the moment and I need to build a temperature chamber. I am using LV 7.1 and I have 4 thermistors being fedback to a daq device. I also have two heaters as part of the chamber but i want to get the thermistors readings and pid control the output to the heaters. I have the program written to get the thermistors readings and average them but im having trouble trying to think how i can pid control the heaters so i am looking for a pid vi. If anyone can help it would be great. Thanks....

NI sells a control toolkit for LV which includes PID control. You can look for it on this site.
If you want to write this yourself, you should start with an uninitialized shift register. A USR allows you to keep data from the last time you ran the VI. There is an example of using a USR in the LV Example Finder and you can probably some more information about it in this site. You will also need to measure the time between runs and then probably calculate the derivative between each 2 runs to see how fast you're approaching your setpoint.
I hope this helps, as a start.
Try to take over the world!

Simple PID Control

Hi there,
I'm using an old version of LV, LV 6i to be exact. Now I am constructing a simple PID control to control temperature of a room. I am using NI PCI-6024E as my DAQ card. But, in the middle of trying to get the program right, I stuck at the PID control. I am using the "simplePID".vi, and connect everything that necessary, the high and low limits, the parameters (P, I, and D), setpoint, take subVI "Temp".vi and connect to process variable and the output of the "simplePID".vi to a chart.
The problems occured when I am running the program, the temperature did give readings like normal, and i set the setpoint and limits, and also the parameters. But it seem like the "simplePID".vi did not responds to these values. As the program is running, i clicked on the "simplePID".vi and see that the value of the parameters inside it doesn't changed to the values that I set earlier. Why is this happening. Am I missing something important.
I attached the pictures and my VI for your reference. Thanks in advance.
Solved!
Go to Solution.
Attachments:
29092012.vi ‏32 KB

Apparently, in the Execution tab, the only option ticked is "Auto Handling of Menus at Launch", and i unticked it, try to run the program, and it worked.
Thanks so much for helping me to figure this out
I have another question, do my DAQ card (PCI-6024-E) can be used with any LV program, the latest or the old versions?
and can it be used with trial version of new LV?
Thanks!

Best design idea for parallel DAQ (via GPIB), PID control and watchdog system

Hello!
I am a starter programmer in LabView, I already understand the basic ideas, and design patterns, like producer/consumer, events state machine, functional global variables, and so on, so the basics...
I started a project a few weeks ago, and first I wrote and tested all of the necessary subvi-s for my project, like the ones initializing my GPIB devices (a Keithley mux and a dvm), controlling/reading out the measured voltage/resistancy values from them, subvi for my Static Analog Output card (I have to drive 7 analog output channels, 4 has to be PID controlled regarding to some of the measured values from the GPIB devices), and another subvi for the analogue card, sending TTL watchdog signals out to my experiment in every 2 seconds.
Any idea is welcomed about suggesting the best design pattern for my project.
The main features of my program would be:
After starting the user interface the program starts with a start-up state, initializes the DAQmx channels and the GPIB devices. The program starts to read out different values from the GPIB devices, including 4 temperature values in every 3 seconds.
In the same loop (?), using PID control, the program sets the DC voltage values of 4 channels (3 to heating wires, 1 to a Peltier-heat pump) on the Static Waveform Analogue output card, the remaining 3 values are constants.
I have to send digital TTL watchdog signal to some relays from the same output card, changing its state in every 2 seconds (not the same rate as the GPIB values are read out).
When the 4 temperatures and the power values regarding to the heating wires are equilibrated after a few hours, the program goes into another state, and signals to the user, that the measurement can be started. During a measurement, I write out all of the measured values to a TDMS file, and there is also some basic calculations "on the fly", like a moving average.
After the measurement done, the user can swap samples, and the program goes into the above state, waiting for equilibration . and so on...
Do you think I should use a Producer/Consumer pattern with events? Or someone would recommend me a better design idea?
Thanks very much!
ps.: I read out lots of values from the Keithleys, so I put them in a cluster. I made a small test vi (attached without the GPIB comm subvi-s), just to test the GPIB comm. So this is the recent state of my project. (all other subvi-s tested and ready to use as I wrote above, like the DAQmx output part)
Attachments:
GUI_Calorimeter_control_image_v2.vi ‏284 KB

Okey
I think it is a better approach if I work first, and after I ask
I go with small steps. For first, now I just want to make a DAQ analog output loop, and parallel a watchdog loop sending out TTL in every 2 seconds.
The main loop in my project will iterate with approx. 10-15 seconds.
I want to check in my watchdog loop, if my main loop hangs up (in that case the PID control stops, but the danger is if the output voltages stay on).
After some readings, I have decided to use a functional global variable.
I have attached the vi, can someone give me advice, what would be the good solution for this purpose?
(I know it is a bit silly what I messed up with the shift registers in the bottom loop, it was some experimenting).
Thanks in advance!
Attachments:
watchdog_funcglobvariable.vi ‏12 KB
Global 1_stop.vi ‏4 KB
analog_output+Watchdog.vi ‏57 KB

Control temperature using USB6221

i have a USB 6221, i m a beginer, so i have a project control temperature by PID, in project i have to control the light 220VAC to change the temperatute, i used moc 3020 anf BTA12, but i can not control it, i have a problem that i can't catch the the zero point phase , any body can help me, i want to catch the zero point by labview using USB6221

Thienbinh,
On the ni.com website, there is a Controls Tutorial which I think will help you get started:
http://zone.ni.com/devzone/cda/tut/p/id/6368
Also, I found this example on PID PWM control by searching ni.com for "PWM" and clicking on "Examples" in the left-hand column.
http://search.ni.com/nisearch/app/main/p/bot/no/ap/tech/lang/en/pg/1/sn/catnav:ex/q/pwm/
If you have the PID toolkit, you can also find examples by going opening up LabVIEW and selecting Help>>Find Examples...
Hope that helps!
National Instruments

PID control to maintain constant heater electrical power?

Hi!
I am looking for a good solution for the following:
I have a heater wire (approx. 220 Ohms). I drive this wire with DC voltage. I measure the voltage drop on the wire, and the current running through it. I want to control not the temperature, but the calculated electrical power (P=U*I) in the range of 1mW to 1W.
Of course the resistivity is slightly different at different temperatures, so that is why I think I need active control.
Maybe someone could give me a good advice?
Thanks very much!

Hi,
Everything is set up for the hardware. I generate the DC voltage with a NI Static waveform card (DAQmx). I measure the voltage drop and the current (via voltage drop measurement on a calibrated resistor connected in serial with the heater wire) with a Keithley DVM via GPIB card. The SetPoint is the required electrical power, the ProcessVariable is the calculated power from the measured U and I. The output is the driving voltage between 0-3 DC Volts, what I amplify with a factor 5.8 with an amplifier connected to the heater wire.
I try to use the PID.vi from the PID toolkit (I already use PI(D) controls from LabView for other heater wires, where I have to control temperature, and they work very efficiently and perfectly) for this purpose.
So far I try to find the proper gain values. My sampling rate is low, approx. 8 seconds. First I tried only the P control (zeroing the I and D gains of the PID.vi), to find a stable oscillation range, so I could go on with the PID Autotune vi. But no luck so far. I think it is also a problem, that this system is not linear: the P is not a linear function of U. Can you suggest how to go on from here?
Thanks very much!

PID control of Counters (PWM)

Hello everybody!!
I work on a closed loop PID controlled problem (Labview 8.5) and I have a couple of questions in order to make some progress!
Firstly, I have to declare that my loop is composed of 2 AI channels (2 accelerometers), 1 AO channel (excitation channel-shaker), and 2 CO (for pulse creation PWM-controllers). The idea is very simple. When the AI (channel 1) value surpass or underpass a predetermined threshold value, then the appropriate CO should be activated in order to apply the necessary control forces and simultaneously to copy my data values of both AI channels in binary style for CPU velocity reasons! BUT, with the PID controller I want to optimize the Duty Cycle value of the pulses!
My questions are :
1) Why when I put Kp=Ti=Td=0 ( = run WITHOUT control) I can copy ALL the AI samples and when I start to activate the PID controller (let’s say for only Kp=0.5) I CAN’T copy ALL the AI samples? Where is my fault?
2) About the PID vi which I use, is it correct or I should use the PID vi for ARRAYS?
3) And finally, about the Boolean statement just before the Case Structures and the Shift Register, is it ok/necessary?
I attach two vis, the ReadBinar .vi is used to read my binary files generated in the end of running of the Control.vi.
Best regards
Grigorio
Attachments:
Control.vi ‏277 KB
ReadBinar.vi ‏162 KB

Hello Zach!
First of all, I want to thank you for your kind interest on my problem!!
I must describe you the desired process with the Control.vi. There are two AI channels writing down the acceleration of a structure in two different points (for velocity reasons I use Binary Type storage for my data). One AO channel for structure sinusoid excitation (shaker) and two CO channels for controlling two solenoid valves with which I want to control my structure acceleration (minimize it as well and fast as possible)!!
In order to help the description, let’s ‘cut’ the block diagram of Control.vi into three pieces (Before While Loop – Inside While Loop – After While Loop).
In Before While Loop section, the main question is about simultaneousness. The DAQmx Start inside the Flat Sequence Structure, do you think that is necessary, ok? I want to run my experiment for 30s and to collect 6000 samples with 200 samples/s. In addition, in the CO DAQmx timing, I have set 200 samples/channel in order to be able to change the duty cycle value because of the conditions inside the While Loop. Do you think that everything in this section works well?
Inside the While Loop, firstly in the DAQmx Read, I have set 200 samples per Input Channel, which is also equal to the AI and AO Sampling rate! Before some days I have put there -1 and unfortunately the total written samples were less than 6000!! My main problem is how I can check all the read data without losing run velocity and simultaneous if one sample is >0 then it goes further to the first PID.vi (left solenoid valve) or if that sample is <0 then it goes further to the second PID.vi (right solenoid valve)!! When a sample has gone to a PID.vi, then I want to tune the duty cycle of the controller (PWM control) as well as possible in order to achieve the Setpoint value for the second AI channel. Are all these possible? If not, what do you suggest me?
In addition I compare the present duty cycle value with the previous one in order to be inside a tolerance value (let’s say 0.1). Moreover, is it correct the Case Structures where I want to share the positive and negative AI samples before going to the respective PID ?
Finally, After the While Loop, I believe that everything is OK. I just finish all the tasks.
I have to mention that I work on a PCI-6289 and Labview 8.5.
With best regards!
Grigorio
Attachments:
Control.vi ‏288 KB
equal within tolerance.vi ‏9 KB
ReadBinar.vi ‏163 KB

I am looking to control a 4-way hydraulic solenoid valve. Do I need a PID control toolset, or can i control the system through my 16E4 daq card and scxi chasis

I am looking to control a 4-way hydraulic solenoid valve. Do I need a PID control toolset, or can i control the system through my 16E4 daq card and scxi chasis

I think you're asking 2 different questions.
The PID control toolset is for using PID loops for control; it's just software.
The DAQ card and scxi chassis are hardware. If you have the appropriate signal conditioning cards in your chassis to control/monitor your solenoid valve, then you can run a PID loop.
I believe the simple answer is: the PID control toolset is the best way to do control, but there are simple PID VI's (even on this website) that you can download and use for simple control.
Mark

Steps to create vi file for PID control in 8.0 pro without specific PID addons.

Per my other posts, I am testing a friend's software to see if this is what we would like to use. I would prefer to use their software for our initial work to help offset the cost of the software. Problem is their software is 8.0 pro without the extra PID stuff. I am curious how one gets started creating a custom PID algorithm to be used in series between an input and an output. I have viewed several tutorials but all seem to simply point at the PID toolkit that is not availalbe to me right now. I realize it might be more work to create one but probably the only option at this point.
To simply the process, lets just compare a single input and output where the software will control the output to obtain to desired input. in tutorial, I was following right along until the PID loop was added and that seems to be just a drop and go type of deal in which would rarely apply to a real work application. I am simply trying to learn how PID systems are written into the block diagrams.
Hopefully my question makes sense.

asdfs wrote:
Per my other posts, I am testing a friend's software to see if this is what we would like to use. I would prefer to use their software for our initial work to help offset the cost of the software. Problem is their software is 8.0 pro without the extra PID stuff. I am curious how one gets started creating a custom PID algorithm to be used in series between an input and an output. I have viewed several tutorials but all seem to simply point at the PID toolkit that is not availalbe to me right now. I realize it might be more work to create one but probably the only option at this point.
To simply the process, lets just compare a single input and output where the software will control the output to obtain to desired input. in tutorial, I was following right along until the PID loop was added and that seems to be just a drop and go type of deal in which would rarely apply to a real work application. I am simply trying to learn how PID systems are written into the block diagrams.
Hopefully my question makes sense.
Take a look at the PID Control Toolkit User Manual . It clearly defines the math used and there is absolutely nothing stoping you from writing that code yourself.
What you will not get by doing it yourself is the auto-tuning as well as all of the supporting and helper sub-VI along with the polymorphic versions that will support arrays of PIDs.
If you write it yourself and it work good please post up your version for others to review or use.
Have fun,
Ben
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction

How to apply notch filter in the PID control

Dear all,
I am using PID control in my positioning stage but the output is every noisy with some fixed frequencies(30,50,150Hz). I want to add a notch filter to take off those noise. However, I do not know how to apply the notch filter to the PID module. Could anyone tell me how and show me example if you have?
Thanks
best
Attachments:
PID_notch filter.png ‏21 KB
PID_notch filter.png ‏21 KB

Hi LYnn,
I am sorry for my late reply. My stage is driven by a voice coil actuator (VCA). The VCA as a resolution of 1 um and range of 6 mm. The NF of the stage does shift when the load is changing. Do you have any advice for controlling such kind of stage?
BTW, as far as I see, the control frequency is determined in the DAQ Assistant settings and its value is equal to "Sampling rate"/"Samples to read", am I right?
Thanks
best
Attachments:
VCA stage.png ‏160 KB

Level Control with PID Control & Pulse-Width Modulation

Hi all,
I have attached my program which I'm having trouble wiring up in the block diagram.... I'm fairly new to labview, but basically I have a level control project with an analog input cistern arm turning a pot for my test tank (configured as DAQ assistant voltage analog i/p) and a pump working off a reservoir (configured as DAQ assistant voltage digital o/p). My electrical side of things is working correctly and I have tested both DAQ assistants I/O's successfully off a basic program, minus the PID & PWM... I found a simple PID control subvi which I think I have wired up correctly, apart from the output variable... I also found a bit of code for PWM using the square waveform vi (far right side of the program) which I have tried to include in the program, but I've been unsuccessful with that. The ideal operation i'm looking for with this project is to be able to enter different values for the setpoint, for the PID to kick in to find that setpoint each time using the PWM to drive the pump, which has a flow rate of 13L/min. I have a manual valve to release water from my test tank which I can set accordingly.
My questions are;
- How do I connect the 'output variable' of the PID subvi to my DAQ assistant digital output(both DAQ assistants are set at 1 sample on demand)?
I have a 'number to boolean array' function, but this gives an error saying that the number of tasks generated are not the same...
- How do I wire up the PWM bit of code? Do I need to include the 'error in & out' tabs?
-Am I on the right track with this program or am I way off the mark?!
Any feedback on this would be greatly appreciated. Thanks for your time,
Richie
Attachments:
PID-RichLevelControl.vi ‏91 KB

Rich-MechatronicsStudent wrote:My questions are;
- How do I connect the 'output variable' of the PID subvi to my DAQ assistant digital output(both DAQ assistants are set at 1 sample on demand)?
I have a 'number to boolean array' function, but this gives an error saying that the number of tasks generated are not the same...
- How do I wire up the PWM bit of code? Do I need to include the 'error in & out' tabs?
-Am I on the right track with this program or am I way off the mark?!
You're a bit off track. You need the output of the PID to go into the PWM generator, and the output of the PWM to be written to the digital output. Right now you have the output of the PID connected directly to the Digital Output in a way that won't work, and the PWM generator hanging off the side not really connected to anything. Also, the PWM generator isn't really going to work since you're generating it at the same frequency as your PID loop runs. Try a simpler algorithm such as on/off control first and see if that works for your system.

NI Robotic starter Kit DANI PID control

Hello
I have this great kit and interested to do a kind of research of PID control on the two DC motors.
I already saw links that can do this job but I noticed that I can not find any technical datasheet having the motor paramters ( Mechanical or electrical)
I plan to bulid a tranfser function usig these paramters and then design a PID controller to make a speed control.
I searched the internet for the datasheet for these motors and could not find.
I think I should use a system identification for these parameters...so the question is
Is it possible to do any experimental system identification for identification of the DC motor parameters without deassebling them from the kit???
and how to do this job using labview??
if any has the datasheets for these motors (TETRIX DC Drive motor, part number 39083) it will be helpful ...
Thanks
A.Hakim

Hello ShishKeBobby
Thanks for your reply, but realy these information I knew, I need more information like a datasheet for this DC motors concerning the electrical and mechanical parameters.
I searched for the tetrix DC drive motor, part no. 39083 on pitisco web site but I could not download the datasheet.
these are the information I need
Motor constants (KT, KE)
Motor internal resistance (Rm) and inductance (La)
Motor friction (viscous friction)
Interia (J)
, thanks
or I am thinking to get these parameters by system identification but I dont know how without disasseblying of the dc motor from DANI and having a benifet from Labview and the assembled Morors in DANI.....
what you think?
Thanks for help
A.Hakim

PID control temperature of oven

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