For discussion of all aspects of measurement and control in the process industries, such as pharmaceutical, power, pulp and paper, chemical, etc.
If you have any questions or comments, please post them here. If you see a question that you can answer, or perhaps add your insight, please use the reply to add to the thread.
Digital versus analog PID
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I built an analog PD controller to control the position of a proportional solenoid. The derivative part operates on the feedback pot voltage.
I used that as a guide for a digital version, implemented in assembly language, running on a Freescale 9S12 processor.
The analog version is stable, but the digital version wants to oscillate with a period of about 45 msec.
The proportional gain (kP) of each is 3.
The derivative part of the analog design has a 300 ohm resistor in series with a 0.1uf cap, with a 300k feedback resistor.
I set up a 1 Hz square wave to run the solenoid from the analog version so I can observe the various outputs from the digital version while it is open loop.
For viewing, I write the signal of interest to a port connected to an R2R ladder network.
The derivative output from the digital version resembles very closely that from the analog circuit, but it is delayed about 8-10 msec.
The routine runs once a millisecond. To reduce noise and get a useable signal for differentiation, I sample the feedback pot once every four msec.
Does the digital version have a chance of working, or is there too much delay?
The solenoid is fairly large and operates on 24vdc, and has a return spring with a force of 10lbs/in. It requires about 3A at 50% duty cycle to get it to move.
You can view the screen capture of the derivatives here:
http://picasaweb.google.com/JohnPizzuto/JSVampireInstallation?pli=1&gsessionid=ri0qbS3mo-_1SrrwfVQ5ZA#5298720393124245314
At this time i have Brand New Bailey IEPAS02 and IMASI23, if there any one interest with my offer, you can contact me at manager@x-code.us. The picture of the items can be send by email.
dear sir,
i am going to make a project on PID pressure controller by using 8051 microcontroller. so i request u, u give me code for this project on my email id
dear sir,
i am going to make a project on PID pressure controller by using 8051 microcontroller. so i request u, u give me code for this project on my email id
I m a moroccan student, and my last year project is to ensure the identification of a rotary kiln (phosphate drayer). we have considered the system as a MIMO system, with 4 inputs: phosphate flow, gaz flow, dilution air flow, commande of fan (creates a depression), and 4 outputs: temperature of foyer, temperature of tube secheur, depression, humidity of phosphate.
to identifie the process we have to choose an adequat method.
can you give me any information that can help me to do this ?
sir i have taken a project on automatic temperature controller .i am final year student.i want to do this project using pid contoller through microcontroller 8051.i need circuit diagram with it's program code
I am designing a heater & controller for a process which needs to heat and maintain water to between 98 and 100 deg C at atmospheric pressure. My concern is that controlling this close to boiling point is likely to be troublesome because of errors in the sensor and/or controller. I fear I could end up applying too much heat and boil off the water.
Am I worrying about nothing? Any suggestions what I could do?
Industrial Ethernet is the name given to the use of the Ethernet protocol in an industrial environment, for automation and production machine control.
Until recently, a PLC would communicate with a slave machine using one of several possible open or proprietary protocols, such as Modbus, Sinec H1, Profibus, CANopen, DeviceNet or Foundation Fieldbus ...
dear who going to read my msg...
i need ur help...im final year engineering student from malaysia
regarding to the title above...i searching for type-2 fuzzy logic.
this type of fuzzy is new for me...for that i need any source code regarding to type-2 fuzzy logic...
i need it as soon as possible because i should study and present to y=my supervisor this monday...pls...
For Atmel/Intel 8051 microcontroller basic tutorials
Tutorial include Interfacing examples of different circuits to 8051 like I/O Ports LED, Switch, Relay, RS232C Cell Phones, GPS receiver, 7-Seg. Display, LCD Display, ADC & DAC, Sensors, Stepper Motor, DTMF Decoder, Keyboard, External Memory with relevant theory, schematics and sample codes in Assembly language & C language
hi, i'm doing a project on shunt active power filter 4 which i need PI processing of bus voltages. can you provide me the code?
my id is magicbhanu_13@yahoo.co.in
regards
Hi,
i am doin project on autotuning pid controller for controlling temeprature and i m implementing zeigler-nicohls method in it so plz send me the code.
dear sir,
i am going to make a project on PID pressure controller by using 8051 microcontroller. so i request u, u give me code for this project on my email id
hi all, im looking for another IC to replace L290 and L291, any idea?
im working in a dc motor controller with feedback control using hall sensor L290 is tachometer converter and L291 is D/A converter and amplifier, the problem is i cant find those IC at local stores.
hope anyone could help me. tq
Does it matter if in a flow control loop if the flow element is upstream or downstrean of the control valve? Typically the control valve is downstream mainly due to upstream straight pipe length requirements for the flow meter would be as high as 35D because if the control valve valve was upstream.
I recently reverse engineered a general motors PCM that was used on the mid 90's GMC/chevrolet trucks. Its based on a modified 68HC11F1 MPU. Well, I figured out how it works, but not how to work it. One thing that it has in it is a very sophisticated PID routine to control the idle. In previous computers, the idle was little more then an afterthought and vehicles didnt idle well. I guess people must've really raised a stink about it because they went all out in the later computers.
Anyway, the idle speed on is controlled via a pintle thats moved in and out by a steper motor. Step it out and the air to the engine increases. Step it in and the air decreases. Easy enough, right? Well, it used to be, but now, not quite...
The PID routine itself is based on the actual percentage of airflow. Later, once all the terms have been added up, the airflow is then translated to the desired steps for the idle air control valve.
There are multiple airflow integrater terms for each state of engine operation, a proportional airflow term, and three derivative terms. One for airflow, which goes along with the IAC valve control and two more. One for fuel, and another for the spark advance, both obviously to suppress transients.
In addition, there are additional routines to construct the desired idle speed based on various parameters, everything from engine temp to the output of the alternator. At the end, the RPM error is constructed from this.
Ok, whew... Now for the question.
Where the hell do I start? Are there any general tuning faqs or liturature to help guide me? Im lost on how to actually tune a full PID control routine.
hi,
i am looking information about how to use lead-lag compensator to control temperature in boiler. if anyone got informaion about this please give information to me.
thanks.
hello
im doing project on pid controller tuning using genetic algorithms,i applied genetic algorithms for a generalised trasfer function, but im not getting any good practical application on pid control so that i can implement it with GA(using GAOT toolbox)
so please kindly give me gud practical example
i need it very urgently
waiting for ur reply
my project submission is on 22nd
bye
Hai...I have a question on how to conrtol the speed of the DC Brushless motor by using PID control. I have done the experiment and take a data. The data is the relation between input pulse and the rotation per minutes of the motor. I plan to use the PID control as the RPM of the motor is the set point and the input is a pulse. From the data I am now trying to calculate the relation between pulse and RPM for the purpose to find the effect of one pulse to the RPM.
My problem here is how to create the PID controller and also how to do the experiment which is needed as a parameter in the algorithm.
If someone have an adea or any reference, please inform me.
Hi,
I am final year eie student, with aggregate of 69% up to 6th sem, in Regency Institute of Technology,Yanam.Affliated to Pondycherry University. I need a job after completing my B-Tech.
Thank you sir.
Control Systems Technology is a comprehensive text focused on the knowledge required by practitioners to both understand and evaluate an existing control system. The text also enables readers to devise and design new control system applications.
The text presents classical and digital control systems, emphasizing careful explanations of the concepts. Multiple examples and solutions illustrate the concepts and the operations required to solve problems. The use of computers to implement practical solutions to problems is also emphasized throughout the book.
Topics covered include:
* Introduction to Control Systems
* Laplace Transforms
* Constrol System Models
* Frequency Response Analysis
* State Space Analysis
* Introduction to Digital Control Systems
* Discrete Control Systems
Each chapter starts with an introductory section that explains the purpose of that chapter. There is also a summary that contains important points presented within the chapter. A set of review questions reinforces learning. Appendices on complex numbers and matrices will prove to be helpful and informative to readers, and solutions to select odd-numbered problems help readers assure themselves that they have a firm grasp on the subject matter.
i am a final year instrumentation student&im cogitating to do my project on microprocessor based temprature controller system.please, provide3 sufficient matter on it.
thanks,
riyaz
b.tech viisem(i.c)
Sir,
I am final year student of electrical engg.I want to do my project based on microprocessor 8051 temprature contoller so please send me guidance about this topic and tutorial.I am hopeful that you will regard my message and give me respond.
Process Automation Control - Online Training/Tutorial
by Peter
Free online training, tutorials and information about standards and technologies used in Process Control and Industrial Automation - Process Instrumentation, Control Systems, Fieldbus, Factory Automation, ...
I am a student of Bangladesh University of Engineering & Technology.I have already sent you a letter. I am interested to work on measurement and control realated to electrical,electronics or communication.So I request you for offering a subject and required working steps realated to that.I am a student of Level-3,Term-2; EEE dept. Thank you.
I am a student of Bangladesh University of Engineering & Technology.I am interesting to do something on measurement or control realated. I want your help for offering a subject realated to this. I am a new person also.
I am implementing a controller pid and urgently need to obtain to the program pid in assembler to incorporate it in a microcontroller 8051. It is
of urgent single necessity needs to finish the controller.
I am a final engineer doing a project about dc motor control with 8051
microcontroller and need the assembly program please send it to me
thanks so much
I am afinal engineer doin a project about dc motor control with 8051
microcontroller and need the assembly program
the motor is a huge one
thans so much
Control 2 loop convergence- Measure Temperature and ONE output control loops.
Two temperature control points: (A)9000W and (B)1500W, where an modulate power 2-100% connected directed (A) and of contactor (B). As it should be implemented the method of control,as "balance" to power supplied and obtain stability?
Please, alternatives, method...
Im trying to develop a direction & speed control algorithm for a wheelchair.
Im using an analogue joystick(basically two potentiometers) and a DSP interface. The DSP outputs PWM to two motors.
This is all ive thought of thus far(it doesnt work though) can anyone offer a method, tip or links to other sites.
PWM1 = direction y + direction x
PWM2 = direction y - direction x
Free information about Automation and Control Systems
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Hi,
I am searching for details about Automation and Control systems. Where on the web I can find more about it. So far I found one site http://www.pacontrol.com with very good content. Are there any similar ones out there?
iam doind a project in level control of a conical tank .pls help me in giving the linearized stedy state and unsteady state equation for the level process.
Has a lot of usefull information about standards and technologies used in Process Control and Industrial Automation - Control Systems, HMI, Batch Control, Fieldbus, Advanced Control, Instrumentation, OPC, ...
Analytical optimal solution to multivariable decoupling control
by www
I just developed a general solution to multivariable decoupling control which is optimal and analytical. It should be, but not confirmed, a breakthrough. Simple testable design examples are provided at http://automation.sjtu.edu.cn/wdzhang/contribution.htm . Comments or suggestions from researchers in this field or interested readers are highly welcome.
Email: wdzhang@sjtu.edu.cn
Brief statement of the problem
Given a linear plant, analytically design the optimal and suboptimal controller such that
1) The closed-loop system is internally stable;
2) The closed-loop response is decoupled;
3) The performance and robustness can be quantitatively tuned.
The plant can have right half plane zeros, right half plane poles, and time delays.
Features
Compared with the classical decoupling control, the proposed method has two important merits:
1) It is applicable to unstable plants.
2) The robustness issue can be naturally treated by those developed techniques.
What is more, the proposed method exhibits some other attractive characteristics:
1) It can be used for the control of unstable NMP plants with time delay.
2) The closed-loop response is decoupled and the design procedure is optimal and analytic.
3) It provides simple tuning rule for quantitative performance and robustness.
4) No state variables and no observer are used.
5) No augmented plant is used and the controller is of lower order.
6) The method can directly deal with integrating plants.
7) It can be used for the design of multivariable PID controllers.
sir,
im doing my project on "level process station"
.i was asked to write a code on the process.
so plz help me out in this regard.
code can be in any language of c,matlab,assembly language.
hope to hear from u soon sir
thanking u sir
vijay
Hi John,
Your book is excellent! I am having trouble understanding the "Two Point Method" you mentioned. It seems you mark the 28.3% and 63.2% points on the process variable ramp. I just don't know what to do after that. Do I multiply this time by 1.5, and use the result as the time constant? Do I then take the whole time value from the Step Change to the 63% PV, and subtract the above calculated time constant and use what is left as the Lag Time?
hi
i am M.TECH student in punjab engg. college. my thesis topic is pid control of radiant heat warmer. i want to know how to tune this. what is its proportional band.
Hi
for one project i need to control temprature with pid controler.
i like use 8052 ,avr or pic microcontroler .
and I need to know the pid code .
can you help me?
with best tanks
regardless of low cost, what is the benefit of implementing pid on microcontroller? i ask you this because many digital pid which used in industries are implemented on microprocessor.
i have a final project about implementing pid on microcontroller to control some medium systems, but i'm confusing about the good issues that it would give
Low cost and lack of any better way are the main reasons. It is easy to build a control algorithm on a microprocessor. In the old days we used analog circuits with op amps. But microprocessors are cheaper and easier to use.
I am a student of COEP college,pune in INDIA.
I am working on project on project "Temperature Scanners"
& i want to implement PID algorithm in it using a microcontroller. So i was refering your material. So, please me any material regarding same to rajendra_darade@yhoo.com.
Thanking you.
I want to simulate a pressure loop and some temeperature loops for a demo. For temperature loops , i used some dead time with first order lag and it works fine. I am not sure what objects to use for pressure loop , since it is faster than temperature loops. Any idea?
Most pressure loops are simple first order loops, but faster than the temperature loops. Some may appear to have about 1/2 sec. dead time, but with others the one major lag is the only thing that matters.
