I'm trying to read data from the Yost Labs 3-Space Sensor Nano into LabVIEW via an NI MyRIO (1900). I was able to set up a sequence that communicates with the sensor through SPI. However, every time I run the program, it just spits out a single value of 255.
I think understand that I need to include something that allows all the bytes to be read. I just don't know how to go about it.
As an example, I'm trying to read the gyros (0x26) which have a return length of 12 and is a vector (float x3).
Here is my labview code
and here is the manual for the sensor. The commands I'm using are on pages 29-33. In the image, 0x2B is 'read temperature'.
Any help would be greatly appreciated! Thanks :)
Edit: i had messed up the wiring so now the output jumps between ~35 to 255. I'm still having trouble getting all 3 gyro values from the SPI read.
Quoting from Joe Friedrichsen in his comment:
The express block that resets the sensor is not guaranteed to precede the loop because there is no data flow between them. The LabVIEW runtime can see two independent and parallel groups and may choose to execute them simultaneously (which on the wire might mean reset comes between loop commands) or in "reverse" order. Add a wire from reset block to create a terminal on the loop.
Here's a picture of the fix.
You may wish to consider stringing the error wire through your program and wiring it to the stop terminal of the While Loop. Currently, your loop will keep running even if there's a fault in your hardware. Using the error wire would eliminate the need for the flat sequence structure.
Related
Is there a generally accepted "correct" way for writing out and reading back in marshaled protocol buffer messages from a file?
I've been working on a smaller project that simulates a full network locally with gRPC and am trying to add writing to/ reading from files s.t. I can save state and start from there when its launched again. It seems I was naive in assuming these would remain on a single line:
Sees chain of length 3
from debugging messages I've written; but,
$ wc test.dat
7 8 2483 test.dat
So, I suppose there are an extra 4 newline's... Is there a method of delimiting these that I can use? or do I need to come up with one on my own? I realize this is straightforward, but in my mind, I can only probabilistically guarantee that <<<<DELIMIT>>>> or whatever will never show up and put me back at square 1.
Use proto.Marshal/Unmarshal:
That way you simulate (closest) to receiving the message while avoiding side effects from other Marshal methods.
Alternative: Dump it as []byte and reread it.
I am part of tractor pulling team and we have Bechoff CX8190 based PLC for data logging. System works most of the time but every now and then saving sensor values (every 10ms is collected) to CSV fails (mostly in middle of csv row). Guy who build the code is new with the TwinCAT and does not know how to find what causes that. Any Ideas where to look reason for this.
Writing to a file is always a asynchron action in TwinCAT. That is to say this is no realtime action and it is not safe that the writing process is done within the task cycletime of 10ms. Therefore these functionblocks always have a BUSY-output which has to be evaluated and the functionblock has to be called successivly until the BUSY-output returns to FALSE. Only then a new write command can be executed.
I normally tackle this task with a two-side-buffer algorithm. Lets say the buffer-array has 2x100 entries. So fill up the first 100 entries with sample values. Then write them all together with one command to the file. When its done, clean the buffer. In the meanwhile the other half of the buffer can be filled with sample values. If second side is full, write them all together to the file ... and so on. So you have more time for the filesystem access (in the example above 100x10ms=1s) as the 10ms task cycletime.
But this is just a suggestion out of my experience. I agree with the others, some code could really help.
I have a set of 16 data stored in BRAM ipcore. Now I have to fetch first 4 at a time and give it to the next IPcore (say FFT) for further processing. Once done with this, I have to feed the next set of 4 data. Is the situation handled by state machine? OR how can i assign values from one ipcore to the next ipcore ? Please help!!
BRAM is dual-ported. Simplest is to make a FIFO out of it with one IP core writing and the other IP core reading.
This will not work for an FFT as that requires a special addressing scheme: the data write order is different from the read order. There you need each IP core to make an address and connect it to the two ports of the BPRAM.
In all cases you need handshaking to guarantee reading only starts after the data has been written of course.
I'm trying to read a Xilinx Spartan 3AN FPGA's 57-bit device DNA using Impact's batch command shell (ISE v14.6) and using the following command line call:
impact -batch file.txt
The contents of file.txt are:
setMode -bscan
setCable -p auto
addDevice -p 1 -file program.bit
readDna -p 1
quit
The response I'm getting from Impact is wrong and changes with each call I make. I know it's wrong because I've instantiated the DNA_PORT primitive in my HDL and am reading out the correct DNA. Here's the last few lines of one of the response from Impact:
Boundary-scan chain validated successfully.
DNA = '111111111111111100000000000000000000000000000000000000000'
Elapsed time = 0 sec.
Has anyone had any success with this command? If so, what am I doing wrong?
With help from Jonathan, I got to the bottom of this.
For the Spartan 3AN FPGA, you can only use iMPACT's batch commands to read the DNA from a blank part that hasn't had any other operations performed on it. Originally I was reading the DNA immediately after erasing the part and performing a successful blank check. These two steps were preventing iMPACT from being able to read the DNA properly on the Spartan 3AN even though it was blank. A power cycle of the FPGA after the blank check results in a valid DNA read.
I imagine this has to do with the behavior of the DONE pin. On this device, the blank check command causes the DONE pin to be asserted and also causes the FPGA to go into an inactive state whether it is blank or not.
Thanks again Jonathan for getting me on the right path.
I am using Arduino controller with MATLAB to build a system that reads in sensor data, which triggers a live feed camera to capture an image for real time image processing. Based on these results further processing is done "after some required delay" through controller. Now the problem I am facing is I cannot read sensor data until the last step of previous stage is completed. I want to be able to read sensor data continuosly and process images even while the last processing stage based on previous image is still executing (because of the delay provided). Thank you for any advice/help. Sorry if my english is bad I hope I'm clear.
You are asking about executing a Matlab code in asynchronous mode. As this maybe hard to control using parallel processes generated by matlabpool (e.g. parfor), you may consider writing your code as MPI. Through MPI you can assign the code lines to be run on each slave process while merging/timing the results can be controlled by the master process.