LabVIEW
Bronkhorst Labview-Flowbus System Integration
@Exchanging7878 wrote:
Hello Dear Mr. Kalbermatter,
Yes, I will use flowbus system, and I will connect them to my computer only one serial connector because it is shown in manual of bronkhorst. So Okay, using only 1 "initiliaze VI" and connect it to 4 different loop will be enough to control 4 different mass flow controller.
No! Not 4 different loops! Since you have one communication port for your multiple controllers you need to make sure to call the according functions serially after each other, not in parallel. That is what happens in the image I show. The main application sends at some point the "configure" message with the serial port to use and an array of node addresses, one for each controller. Then the application can send a "setpoint" message with the new setpoints for each controller. Then it sends periodically a "read" message to have the message handler pass back the current value readings for each controller through a notifier. Whenever a new set of setpoints needs to be applied, a new "setpoint" message is sent. There also is a "close" message to close the serial port and terminate the message handler. That's it.
The handling of multiple controllers is done through a loop with the array of node addresses as input. For each node address the loop executes once to do the "write setpoint" or "read direct" value. If you need to do some units checking or whatever you would either add that to the configure state or another separate message state that does whatever needs to be done but you do not want to add such stuff to each read operation! It costs time to send such messages and wait for the response, and doing that umpteen times per second for something that simply never will change during normal operation of your system is pretty stupid. Usually you setup your system once and after that, those things never will change. So there is no use in having this done over and over again during normal operation.
