Implementation of Digital PID controller in FPGA

[Altera_Forum]

I'm trying to implement a PI controller in FPGA using schematic entry method in altera quartus II . I'm using the following equivalent PI controller equation, 

 c(n) = c(n-1)+kp*(e(n)-e(n-1))+Ki*T*e(n-1)    where,  c(n) = controller output  Kp= proportional constant  Ki=integral constant  e(n)=Reference -actual input  T=sampling period    I'm implementing it for 8 bit data. I couldnot implement c(n-1) in the above equation using schematic entry. Can someone help me implement this? I would be grateful if you can suggest me other ways of implementing PI controller like in VHDL.

[Altera_Forum]

Mr. Frank, 

you are right, and i don't want a supervisor for my research because i already have one:). i just didn't see any comment since August,2010.  now i'm working to understand the control and design part of digital PID , and the next step after finishing the simulation of the PID is to implement it based of FPGA.  I have only one question, i'm going to buy Altera DE2-70 , according to your experince in this field do you think it's sufficient to implement the PID.  Please advice me which board is the good for my research:unsure: .  thanks in advanced

[Altera_Forum]

I tried to attache the board link of Altera DE2-70 but it's not allowed yet for me :(

[Altera_Forum]

--- Quote Start ---  I tried to attache the board link of Altera DE2-70 but it's not allowed yet for me :(  --- Quote End ---    You'll need to clarify what you mean by "board link".  The board has an Embedded USB-Blaster circuit on one of the USB connectors (it should be written on the PCB silkscreen next to the connector). I think its the outer-most connector (nearest the edge of the board).  The other two USB connectors are connected to a USB PHY for custom applications.  Cheers, Dave

[Altera_Forum]

--- Quote Start ---  You'll need to clarify what you mean by "board link".  The board has an Embedded USB-Blaster circuit on one of the USB connectors (it should be written on the PCB silkscreen next to the connector). I think its the outer-most connector (nearest the edge of the board).  The other two USB connectors are connected to a USB PHY for custom applications.  Cheers, Dave  --- Quote End ---    The board link is the website link, sorry for confusing you :)  "To be able to post links or images your post count must be 4 or greater. You currently have 3 posts.  Please remove links from your message, then you will be able to submit your post."

[Altera_Forum]

--- Quote Start ---  The board link is the website link, sorry for confusing you :)    --- Quote End ---  Ah, I see.  The DE2-70 has plenty of logic for a PID controller. The lower-cost DE0-nano, BeMicro, and BeMicro-SDK boards would also have enough logic.  What is just as important, is what are your I/O requirements? Does your PID controller need an ADC or a DAC? How are you going to interface to the real-world?   You need to look at both the FPGA board and the interface boards, and make sure you can connect them together without too much work.  The DE2-70 and DE0-nano interface to boards via their GPIO headers. Terasic have some ADC/DAC boards.  The BeMicro and BeMicro-SDK boards have an 80-pin edge connector. You can connect a PROTO board to that header for interfacing to custom logic.  Cheers, Dave

[Altera_Forum]

--- Quote Start ---  The DE2-70 has plenty of logic for a PID controller. The lower-cost DE0-nano, BeMicro, and BeMicro-SDK boards would also have enough logic.  --- Quote End ---   I absolutely agree. I can tell, that I have implemented a power electronics controller with multiple PIDs on a small (8K LEs) Cyclone II, DE0 Nano has factor 2.5 more.

[Altera_Forum]

--- Quote Start ---  I absolutely agree. I can tell, that I have implemented a power electronics controller with multiple PIDs on a small (8K LEs) Cyclone II, DE0 Nano has factor 2.5 more.  --- Quote End ---     How about the Max7000 ,I got one free . is it plenty of logic for a PID controller???  If not i have to bye another board.  Gazal

[Altera_Forum]

--- Quote Start ---  How about the Max7000 ,I got one free . is it plenty of logic for a PID controller?  --- Quote End ---   Not at all. MAX7000 is a CPLD, a reasonable solution for pure digital logic designs. Even the largest MAX7000 with 512 macro cells won't allow more than a rudimentary (e.g. 8 bit data width) controller. A recent development kit like DE-0 Nano would make much more sense.

[Altera_Forum]

--- Quote Start ---  Not at all. MAX7000 is a CPLD, a reasonable solution for pure digital logic designs. Even the largest MAX7000 with 512 macro cells won't allow more than a rudimentary (e.g. 8 bit data width) controller. A recent development kit like DE-0 Nano would make much more sense.  --- Quote End ---    well, i am not working on a conventional PID, so i'm a little bit worry if the Nano will be plenty to apply an intelligent algorithms.

[Altera_Forum]

--- Quote Start ---   i am not working on a conventional PID, so i'm a little bit worry if the Nano will be plenty to apply an intelligent algorithms.  --- Quote End ---    So implement your algorithm and synthesize it in a device.  You do not need a board for this. Just select the same device as used on the DE0-nano and see if it has enough resources. If it does not, then try a larger device, or try a larger device from a specific evaluation board, eg., the DE2-115.  Cheers, Dave