Best Way to Control Solenoid Valves?

[NT_Engineer]

I am in the beginning stages of designing a LabVIEW program that will need to control 13 solenoid valves individually. The solenoid valves will control 13 gas lines that will be fed into 1 gas analyzer.  Each solenoid valve will need to opened one at a time, and the %CO2 concentration will be logged in Excel with the corresponding valve number and time.  This process will be repeated for 14 days continously.

For Example:

  Valve     %CO2     Time
     1            10%       10:30
     2            9.5%      10:31
     3            9.75%    10:32
     ...            ........      .........

What would be the best method to control these valves in LabVIEW, keeping in mind  synchronization and timing is very important for this project?

Thanks

[StevenA]

What are your timing requirements.  How fast and how deterministic do you need to cycle these valves.  You show in your sample data a 1 second time interval.  Is this typical?

[NT_Engineer]

Sorry, I meant to put an "am" beside the times.  It is going to take at least a minute for each gas line to be sampled by the gas analyzer, because the gas from the previous line needs to be completely flushed out so that it doesn't effect the measurement with the current valve. Also, it will allow the reading on the analyzer to steady out.  The valves themselves only take a few milliseconds to respond.

[johnsold]

Also, will the valves always be operated in the same sequence or can it vary from run to run?

What will the system do if you have a power outage?

If as SteveA asked you are doing this on a one second interval, you will have over a million lines in your data file. Do you really want to open and close the file a million times? Do you really want to handle that with Excel?

How much user interaction is required while it is running?

Lynn

[NT_Engineer]

It will be the same run-to-run.  Also, I mentioned in my previous reply that each sample will take at least a minute.  I just forgot to put an am next to the time.

User interaction with the program will be minimal.  The user will enter some information about the test before starting like: Name, length of test, Operator Name, etc...  Also, they will need to pause the test at least once a day to peform routine tasks on the physical apparatus and resume the test after the task has been completed.

[StevenA]

What is the voltage and current of your valves?

[NT_Engineer]

They are 24 V solenoid valves.  We are going to use the NI 9472 to control the valves.  I am really interested in how to synchronize these valves sequentially one at a time and record %CO2 concentration and time of measurement to an Excel file

[StevenA]

Are you using the 9472 in a USB chassis or compact RIO?  Lot's of questions I know, but it makes a big difference.

[NT_Engineer]

It will be in the USB chassis

[StevenA]

So do you have an analog input that will be used to measure the results from the gas analyzer?