I am attempting to create a PID controller for an air hose and valve system. The system consists of an Omega FC-22 flow computer, a motorized valve, and a down stream sensor to measure cubic feet per minute (CFM). The control loop goes as follows: user punches in desired CFM -> valve turns until flow computer = desired CFM -> valve corrects itself when desired CFM exceeds +/- 1 (or so) CFM. The upstream airflow is not part of the control loop, once it is on, the valve is used to regulate it.
I understand how PID controllers work in Simulink, but am not sure how to go from a transfer function and PID controller to the scenario above. Also, another issue I face is figuring out how to interface the Omega FC-22 with Simulink, which is a critical portion. Any and all help is appreciated.
**I have attached the user guide for the Omega FC-22
https://www.omega.com/manuals/manualpdf/M2572.pdf
You'll have to make Simulink write the CV of the PID to the valve. Typically this is done via a 4-20mA signal from the controller (pc in your case). You'll probably have to see what types of input signals your valve supports and wire accordingly.
The PV of the PID will come from the flow computer's Modbus RS-485 interface. The manual didn't show a ModbusTCP or RS-232 option. You'll have to use an RS-232/RS-485 or a USB/RS-485 adapter. Then read in the appropriate flow from the modbus registers listed in Appendix C of the Omega manual.
The set point of the PID should be easy enough. Just have a way for the user to enter it on the pc and send that value to your Simulink code.
Related
I want to create a basic project in Vivado that takes a value that i input to a client, which is sent to a server I made (in C), and then the server writes that value to a peripheral in Vivado, and then that data in the peripheral is sent to an output pin that assigns to LED's, making the LED light up.
Basically I want to go from client-->server-->peripheral-->LED lights up
For example, in the client (a GUI) I want to give it a value such as 0011, which is received by the server. Then the server writes that value to the peripheral which will then make, in this case, LED0 & LED1 not light, but LED2 & LED3 will light.
I know how to make an AXI4 peripheral in Vivado, and the client-server (TCP/IP) has been made. My question is what code/design block I would need to then take the data written to the peripheral and assign it to the LED's?
Should I make the peripheral a Master or Slave? Overall confused how should i proceed from here. I am using a Red Pitaya (Xilinx Zynq 7010 SoC) connected by an Ethernet cable to my computer.
Also, I thought of running the program on the Red Pitaya by loading the bitstream on to it (using WinSCP) by running the command
cat FILE_NAME.bit > /dev/xdevcfg
in PuTTY (connected to the Pitaya by IP address), then running the server on the pitaya, and then sending the signal from the client for the server to receive. Is that the correct way of approaching it?
If my logic is off in anyway please let me know
I am somewhat thrown by your statements.
First you say "I know how to make an AXI4 peripheral in Vivado"
Next I read: "Should I make the peripheral a Master or Slave?"
Maybe I am wrong but to me it says you don't really know what you are doing.
Simplest is to:
Instance a zynq system.
Add the IP with the name "AXI GPIO". (Which, by the way, is an AXI slave.)
Run the auto connection.
Assign the right I/O pins to the GPIO port. (check your development system manual)
Build the system.
By the way you find the address of the peripheral in the address tab and it normally is 0x0080000000.
You wrote that you made a server (TCP/IP). "All" it has to do is write the received value to a register in the GPIO block. (Here I assume Xilinx has a document which describes how the GPIO block works and has example GPIO drivers.)
In QSYS I have an ADC, PLL and an Avalon-MM Read Master to access the internal ADC of the Altera Max10. The control and user interface of the Read Master are exported.
Now I struggle to setup the control interface to access the ADC channels. Mainly following signals:
control_fixed_location
control_read_base
control_read_length
The interface description is:
The block diagram for the Read Master is:
Questions:
- How do I need to set the control signals to access the ADC channel x?
- Where can I find the base address for the ADC implemented in QSYS?
Attached is the quartus archive. Maybe someone can give me an example to simulate this interface in ModelSim.
Thanks in advance!
I have an answer to your second question. I am struggling myself with the first question.
Where can I find the base address for the ADC implemented in QSYS?
I know two methods to find the base and end address of a component.
One is to open the System Contents view (standard) and scroll to the right side .
I am not permited to embed images yet.
There you see a row named Base and End. Here you can find the addresses.
The second method is to open the Address Map. Should be located in the same column as System Contents, or you can select View in the top left corner and select it there.
Have a look. You should be able to find it yourself with this information.
What i use when i am searching for examples or prebuild designs is the altera website. Here a link for you https://cloud.altera.com/devstore/platform/
Probably you like this one: https://www.altera.com/content/dam/altera-www/global/en_US/pdfs/literature/hb/max-10/ug_m10_adc.pdf
The configuration is complete in QSYS? Like selecting channels and Sequencer in your ADC Block. Selecting the right input clocks and the right frequencies?
You wrote:
In QSYS I have an ADC, PLL and an Avalon-MM Read Master to access the internal ADC of the Altera Max10. The control and user interface of the Read Master are exported.
Have you created a clock for your PLL? When i want to simulate a clock signal for a QSYS system i export the clock signals and define the wanted clock in an additional file.
When you go one step further and include a nios2 processor i recommend to have a look at the altera_modular_adc.c file.
*edit
If you haven't assigned any base addresses there is a function in QSYS which does the job for you.
In System (Same column as File) -> Assign Base Addresses
I'm trying to implement S-MAC protocol on waspmote xbee sensors and i know it has its own CSMA/CA. So first of all I need to understand the basic of xBee collision avoidance.
Two senders set up in api mode in libraries and both periodically sending single bytes to a common receiver. I reduce the delay and many changing in libabries to make collision and to see how algorithm works. But when i monitor data at the receiver all looks as expected at the receiver .. byte1, byte 2 .. byte1, byte2.
Do u have any idea how can i make collision?
Are you sniffing the 802.15.4 traffic? That's the only way you'd see a collision.
The XBee module buffers the data you want to send, using the host communication parameters (baud rate, API mode, etc.) and then sends it out over 802.15.4 at 250kbps. The module has all of the collision avoidance built in, and will retransmit as necessary to deliver your message. If it's unable to deliver after some number of transmission attempts, you'll get a Transmit Status frame indicating failure.
On the receiving end, it buffers the data and delivers it to the local host using local serial settings (baud rate and API mode).
If you're trying to implement S-MAC, you need a different radio processor where you have low-level control over the radio. The XBee module provides an application layer and handles the MAC layer itself.
I am new to the Zedboard and am working up to transferring a complex hardware accelerator I currently have working on a regular FPGA board. Anyway I want to walk before I can run so have done the Zedboard speedway tutorials and am now toying around with small projects. My first of which being an simple adder accelerator:
-Send 2 numbers to the pl(programmable logic), to reg a and b
-the pl adds the numbers
-an interrupt to the PS(CPU) signals the computation has finished.
-In the ISR the PS reads the result from reg c
For this design I am using 3 registers (a,b,c) in the AXI interconnect, I have created the IP templates using CIP.
Basically though what is the best way send a control signal to enable the addition to the PL. So how should I signal to the PL adder that I have loaded the two numbers in reg a and b and now want to add them?
-Should I create a 1bit signal GPIO interconnect, add a 4th 1 bit control register to the IP? or is there a more 'stylish' way to do this by using the BUS2IPdata signals?
-Or is there another way to create custom PS to PL control enable signals?
Many thanks
Sam
Current idea:
-Build a switch in the user_logic HDL based on the BUS2IPWrCE, so when this is asserted to write to reg B I can then signal an enable signal to my adder? Or will I run into some concurrency issues with the data not being fully written straight away?
So to do this I have created the AXI perph using CIP, then modified the used_logic and two new ports, en and interrupt. Following these instructions I employed these external connections.http://www.programmableplanet.com/author.asp?section_id=2142&doc_id=264841
I then connected these two external connections to GPIO interfaces to provide the required functionality.
In your larger designs, it will be difficult to get performance using a GPIOs to control the scheduling of your accelerators. I suggest setting up FIFOs of command blocks between software and hardware.
For example, your peripheral could implement an AXI Stream slave, to receive commands from software, and an AXI Stream master, to send result indications back to software.
It can assert an interrupt to indicate that there are values in the response FIFO.
For higher performance, set up these FIFOs in DRAM and use AXI read/write masters in your peripheral.
I want to learn and implement CAN BUS protocol. I have implemented UART,SPI,I2C and One Wire Bus protocol using MSP430 Launchpad in software. Now I want to learn about CAN Bus protocol. I have mBed LPC 1768 Cortex M3 Development board. mBed has Can Bus Library but I want to write my own library so that I can learn it in detail, i.e. the way I did for other communication protocols.
I am not able to find suitable resources to start with and the material appears to be scattered on net. Can any one guide how do i write and implement CAN Bus protocol with the development boards available with me.
Thanks
Developing CAN library is relatively easy as compared to I2C or SPI. This is because CAN Controller of your Cortex will take care of most of complex things.
To transmit the data, You have to write ID and Data in designated registers and set bit to transmit data.
This Application note from NXP can be very useful for you.
I would recommend you to implement following functions:
InitCAN - This should set specified Baud Rate of CAN.
SetFilters - Most CAN Controllers come with Acceptance Filters, So it's good to have that
SendData - Make sure you accept Parameters like ID_Type and RTRs etc.
RecieveData - This can be blocking or Interrupt based.
Before beginning, do read CAN Basics to understand. Application notes AN713 and AN754 from Microchip is a good source. Also Vector's site and Wikipedia Article.
Plus, You can always post your doubts here or on Electronics.StackExchange.com :)
Okay so this post is quite old but people may look at it again so:
First of all Can bus is not user friendly protocol like USART or IC2 at all so you have to be very precise about your can bit timing there are tools for that but I suggest you to calculate them by hand. For a microcontroller I would suggest STM32 and be away from PIC series in my opinion. If it's only CAN-BUS without higher level protocols such as SAE J1939, steps are pretty simple and straight forward:
1)Initialize Can
2)Put CAN to configuration mode and remember that you can set baudrate, mask and filters only in configuration mode!
3) Set the baud rate registers.
4) Set the mask and filters. If you need to receive all messages just simply set mask to 0x00. Then filter will be do not care.
5) Set the CAN to the normal or loopback mode. (loopback mode is used for debugging purposes mostly.)
Some remarkable points people try to implement can at the beginning may miss:
*** You need at least 2 working CAN nodes for successfull transmission. (of course with matching baud rate). So if you want to send some data via CAN with 1 node it will not be succesfull. Because your transmitter node will not receive ACK.
*** Most likely you will need a CAN tranciever. Do not forget to put a 100 ohm or similar value resistor between Tx and Rx pins of your tranciever.
I used the software canking to talk to a mcp25050 when I learned how to implement can protocol using an hcs12 dragonboard. It helped a lot because canking will initialize everything for you when u go on the bus and all you have to do is learn how to write and recieve. If you want to learn how to initialize the steps are:
Enables can bus by setting bit on CAN Control Register 1
Enable can initialization Control Register 0
wait until can bus is in initialization mode by checking control register 1 bit
Enables can bus by setting bit on CAN Control Register 1 again and set clock source - Ethier bus clock or eclock
set prescaler baudrate and Tq with Bus timing register
set sample time and prop_seg1, prop_seg2, and phase_seg
set acceptance id on Identifier acceptance register 0-3 or 0-7 - to set your can to recieve everything set those to 00 because when doing a compare the can bus does a ones complement compare with the id coming in
set Identifier mask register 0-3 or 0-7, if you want to not care about any of the bits set them all to FF
set identifier acceptance control register to 32 bit extended or 11 bit - i use 32
set Control Register 0 back to normal mode
wait until bus is normal mode by checking Control Register 1
after this you can start changing registers or reading data to do this you must select the empty can buffer, write your id to write or request data, and then input the address, mask, and value in the 3 transmitter registers if writing and then specify the dlc (3 if writing and 8-1 if reading). to transmit the id and data you then have to set the can transmit flag to equal the can Transmit buffer selection.
** depending on what id you use bit shifting can be tedious so if you are having a problem I would suggest debugging and looking at what your Transmit buffer selection registers are holding. I had this error because i did not shift correctly when i was sending messages to the mcp25050
If your MCU supports CAN Bus, you should start from the related datasheet.