Hi EduU,
I was answering your last question. I thought you had progressed on the first portion.
I wish I had LV installed on this PC, as I would prepare a quick example for you.
I'll try to have a look at it tonight, if time permits.
In the meantime, let me try to explain how I would do it.. I don't like using Delay/Wait because if misused, they can be a source of problems, especially if longer than 1 sec.
First, I would need to determine the aquisition rate (how often data is sampled).
Then I would determine how often I want to write.
Usually, if I write slower than I acquire the data, which is often the case, then I would have producer / consumer loops. The producer would do the acquisition od data and pass it to the consumer for processing, which includes writing to file.
The trigger for the consumer loop would be time based. If there is not too much data, you can store the data within a shift register of a producer loop and send it all at 1 minute intervals to the consumer loop using a queue. The consumer loop would have a state machine that gets the data and state from the producer loop. The state would be writeToFile (or something similar). The other approach would be to queue up the data and continuously send it to the consumer loop. It would monitor the elapsed time and trigger its own write to file process (I don't want to use the word "event" because it may not be handled as such). The latter may be better because it may prevent loss of data aquisition since the producer loop would do one thing only, to acquire data and put it in a buffer to send it to the consumer loop.
In the consumer loop, since you would be checking the date at 1 minute intervals, you could also check the date. If the date has not changed (now = filename date), then you keep writing to the same file. As soon as the first ring of midnight strikes, you would detect the change of date and create a new filename and start writing to that one.
Since you are writing to the file at a rate of once per minute, I would open / write / close the file in order to make sure that the data is saved. Notice that I did not say "open / read entire file / append to end / save / close". There is a reason for that. You can keep tack of the last file position and it becomes the offset to where you want to append the new data. Reading the entire file is very inefficient and not necessary. Since you have that "offset", you could save it into an array. To make your life easier, you could put it into a 2D array along with the timestamp. You could even save that info for later use (there's a few way of doing this).
Am I missing anything?? (questionning myself.... probably 😄 )
Hope this helps.
R
