Recording Start STop Times

[DavidTas]

I have  an NI USB 6501 - I am ebarrased to say that I can't drive the Labview Software.

My application is I believe very simple - I want to record the start time/date and end time/date of a switch action.

I CAN setup Labview Signal Express to display True/False values, I can display a graph

I CAN output the recorded log to Excel.

However - The log only shows me the start time/date that the RECORD was started and then shows me

incremental counts 1, 2, 3, 4, 5,....n with a 0 or 1 ( True/False) state for that count value

Perhaps if I explain what I want to do someone might be kind enough to clue me.

I have a number of Irrigation Pumps that I want to record their Run Times over a 6 month Irrigation Season.

Each Pump has a Switch that is closed when the Pump is in operation

Typically a Pump would run 4 to 6 hours at a time - perhaps twice a day.

The output in Excel might look something like tise

I/O Line 1 = Pump 1 Start Time 10.06am 4 Nov 07 End Time 15.36pm 4 Nov 07

I/O Line 2 = Pump 2 Start Time 11.00am 4 Nov 07 End Time 17.00pm 4 Nov 07

I/O Line 1 = Pump 1 Start Time 17.40pm 4 Nov 07 End Time 22.00pm 4 Nov 07

And so on = there are 9 pumps in the Scheme at the moment

In truth I could write a basic program to service an I/O Port line on a PC Bus - But It is beyond me to program

the USB Device. It may well be that I have chosen the wrong I/O device for this project.

At the time ( and still) USB seemed an elegant way to go.

Thanks in advance dtasker@netspace.net.au

[Dennis_Knutson]

I'm not sure what you are asking for. Signal Express is an application and I m not sure it has the flexibility to format data the way you want. With LabVIEW, you can certainly do it. What exactly are you having a problem with? There is the DAQ Assistant and numerous shipping examples. If you have tried to write a program, then please explain exactly what doesn't work. Attaching the program would be the best way to see what is going on.

[Mark_E]

Welcome to the discussion forums, DavidTas!

It sounds like you want to do change detection. There is a KnowledgeBase that lists which devices support change detection, and unfortunately the PCI-6501 is not one of those devices.

If you had the full version of SignalExpress, you can use alarms to trigger certain events or invert the line, etc. when user-defined conditions occur. You would have to manually inspect the logged data and compare it to the alarms to determine when the changes occurred and ignore all of the other data. If you have the lite version (that comes with any DAQ card), it is meant to be a data logging software package with some signal analysis built in, but doesn’t offer alarms.

The best solution would be to use LabVIEW to program some very simple state machines to determine if the signal is high or low and do something when the state changes, such as create a timestamp.

The more you want to do with any application, the more tools you’ll need to do it. It sounds like you might actually have LabVIEW, but are unsure of how to approach this application? If so, when you first open LabVIEW, you can choose VI from Template and navigate to VI » From Template » Frameworks » Design Patterns » Standard State Machine or look in the Example Finder (Help » Find Examples) from LabVIEW.

I hope this clarifies what you would need to go about building your application.

[DavidTas]

Thank you Mark,

I began to think that the 6501 was not the right device - Before I purchased it I explained the nature of my application and the need for software.

To an NI Sales Engineer.

The NI Sales Engineer advised me to buy the 6501 as it would be able to do my "simple" application, She also explained that the Signal Express software would continue to allow me

to export to Excel after the 30 day trial Period. But as you say the 6501 is probably not the right device - plus the software doesnt format to the

Time/Date stamp I need.  Thanks for your feedback.

I may just build a port based I/O card - after all I really just want to be able to record how long a pump is runninge each day. ( 9 of them)