Help write Vi to acquire data and write to file

[Farside1]

Seeking knowledgeable help to setup a VI to acquire samples from 2 analog input channels, scale data, and write to file.
I have attached the a power supply with external current excitation (4-20mA loop) and verified signals.


hardware specs:

PCI-6250 DAQ Multifunction series

Sensors current loops connected as "differential pair", "external", and "249" ohms resistance value.

Tasks created
RH % = Analog Input 0 (ai0)
Temp = Analog Input 1 (ai1)

Created custom scales for 4-20mA input
RH %
min 4mA = 0 % relative humidity
max 20mA = 100 % relative humidity


Temp
min 4mA = -40 C
max 20Ma = +180 C


The simple setup would be a manual start button to read, scale, and write data to text or spreadsheet file. I would like to have option of starting a new log file or append existing file.

The wish list -
Connect to a Watlow F4 Controller thru serial port and control start/stop it's profile (I manually load a profile into memory).

I have no training and little luck going thru the tutorials (introduction to labview 6 hours, learn labview in 3 hours, etc..) and examples I have downloaded and tried to modify. I have tried working in MAX creating tasks, virtual channels, but when I drag n drop a task into the front panel then try to input parameters in block diagram I get lost and generate more errors than data.


Thank you,
Phil Johnson
Hardware Technician
http://www.digitalpersona.com/

[AdnanZ]

Hi Phil,

I hope you are doing well today! Did you try the examples in LabVIEW which can be found in Example Finder (Help -> Find Examples)? Since you are a beginner, I would highly recommend that you start the process step-by-step. Is it possible for you to use the DAQ Assistant and read from a single channel? You could output the data to a Waveform Graph and see if you get any data over there. Also, try reading and writing to a spreadsheet file in a different VI. If you are still getting errors for both these functions, list them out over here and we should be able to help you out. Also, I would highly recommend that you take some courses taught by professionals from National Instruments. More information about that can be found here:

NI Training Courses and Certification Exams