LabVIEW
multiple com port read delayed (parallel/ continous)
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Content Cleaner
Why are you using 4-5 microcontrollers to get different signals? 
Is it possible for you to use a single microcontroller to get 5 different types of signals? How many analog I/Os does you controller possess?
Another technique you can employ is by Multi-Core Programming which uses different cores of your PC's processor (provided if your host machine has multicore processor) to process tasks in parallel (each thread running in it's own processor).
Regards.
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Content Cleaner
Hi!
Why are you using 4-5 microcontrollers to get different signals?
-I divided the µC to their tasks... so i have 2 µC which collect a external clock signal. 1 is used for pressure sensoring and 1 for displaying, measuring und controlling temperature.
Is it possible for you to use a single microcontroller to get 5 different types of signals? How many analog I/Os does you controller possess?
Iam using external clock pins... so iam limited to 4 pins/ µC
Another technique you can employ is by Multi-Core Programming which uses different cores of your PC's processor (provided if your host machine has multicore processor) to process tasks in parallel (each thread running in it's own processor).
Sounds super promissing but also super complex ... I will give it a chance 😛
but did you check my program ... is that the way i should work ?
best regards
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Content Cleaner
In your code, you have used a while loop with no 'delay'. Since you're using your PC, this loop is oftenly called 'greedy loop' which takes all the CPU resources. Now your CPU is only processing what's 'insde' the loop and not taking care of nodes outside of it, where it has to initialize your COM ports.
Second, you don't need to reinforce to CPU to initilaize your COM ports by using flat sequence structure. I see alot of numeric processing with feedback nodes which takes up good cycles of your CPU, thereby unable to listen to other COM ports.
Use seperate Timed-Loops for both COM resources with carefully selected clocks and timings. I would suggest you to first acquire data from both Arduino resources using seperate While loops with same delay. Observe if data you're interested in is being fetched in a nice synchronized way.
Here is a webcast discussing techniques for Data Acquisition.
Regards.
Ok, we have some issues here.
1. You loops for reading the serial ports are not needed at all. You can just let the termination character stop the VISA Reads instead of trying to find it yourself. You already have the termination character settings correct based on the default values of the Configure Serial Port. So just tell the VISA Read to read more than the longest message you would expect. I like to use 50.
2. The sequence structure is not needed at all. You have data flow to determine the order of execution.
3. Everything inside of a loop must complete before the loop can iterate. This means that all of your measurements must be found before the read can be done for the next sample. As long as data is coming in on all of the ports, this should not be an issue.
4. You can likely clean up a lot of your code by using a Chart instead of a Graph. A chart keeps a history on its own while a graph does not.
@NapDynamite wrote:
In your code, you have used a while loop with no 'delay'. Since you're using your PC, this loop is oftenly called 'greedy loop' which takes all the CPU resources. Now your CPU is only processing what's 'insde' the loop and not taking care of nodes outside of it, where it has to initialize your COM ports.
With proper serial communications, this is not an issue since the VISA Read will sleep waiting for the data to come from the driver. However, the reading 1 byte at a time is just asking for trouble. Let the termination character settings built into VISA do all of the work for you.
@kohlmeise wrote:
1. You loops for reading the serial ports are not needed at all. You can just let the termination character stop the VISA Reads instead of trying to find it yourself. You already have the termination character settings correct based on the default values of the Configure Serial Port. So just tell the VISA Read to read more than the longest message you would expect. I like to use 50.
I tried but the signals started to mix ... maybe i forgot to mention that the incoming signal on the first com port consist of 4 different signals...
Sounds like you have a bad format for your data coming out of the microcontroller then. Since you have 4 signals, send them in a single message seperated by commas (,). Then you just do one read and you get all 4 with no worries about mixing them up.
kohlmeise wrote:
3. Everything inside of a loop must complete before the loop can iterate. This means that all of your measurements must be found before the read can be done for the next sample. As long as data is coming in on all of the ports, this should not be an issue.
Iam not sure if i get your point right .... the amount of data should be the same at each port ?
No, you just need to be getting messages from all of your ports at about the same rate.
