Yes, that is correct. We have successfully sent two commands using the attached VI (which is the serial write and read vi found in LabVIEW's examples).
The first was 'r050.0\r', which is the send digital setpoint (p.14 of the serial users manual). The previous command simply sets the output pressure to 50% of the provided input pressure. We also have sent the command 'rRM3\r', which reads the local pressure.
I would assume these two commands are all you would need to make a waveform chart, but im not sure how to arrange the VI to allow pressure measurements to be read continuously for graphing. My logical idea was to put a while loop with a stop button around the VISA write block, to send the command to read the local pressure at every iteration of the loop, where the time between iterations is controlled by a wait or delay block.
I did mess around with this a little, but could not get it to work, mainly because I wasn't sure how to include both of the write strings, rxxx.x (any number from 000.0 to 100.0) and rRM3. I figured the first one will be input by the user, and the other could be a string constant. But then would you need two VISA write blocks, or can you somehow combine the two strings and connect it to the one input termnial of the VISA write block? Because I don't know much about LabVIEW, I was hoping some of you more experienced programmers could give me some suggestions.
To give you an overview of what we want to do, right now our main focus is to be able to chart the pressure values against time, and then ultimately write a VI, so that all we have to do is hit a start button in LabVIEW, and the pressure regulation will be controlled completely by some other variable and NOT by user input. For example, in our case we would like to regulate pressure based on the temperature of the two metal blocks which are being used for an imprinting process. For a sample run, we would hit the start button: We would most likely want the pressure to be very low, around 1 or 2 psi, until the temperature of the blocks heat up to an arbitrary value, say 100 degrees celsius. At that point the pressure can be increased to another arbitrary value, for instance 40 psi. The same would be true for the reverse process: when the blocks go below that temperature, the pressure is slowly lowered, and after the full run, set back to 0 psi. This will be a much more complicated project, but the first step would be charting those pressure values. Suggestions are welcome for both problems, though!
If anyone needs anymore information or files pertaining to the pressure regulator, let me know. Thank you very much for all of your help.
Ray
