High Voltage (0-40V) DAQ - USB

[swiftmoun]

Hello,
I am looking to using labview as a tool to give me real time measurements for heat dissipation into a fluid.
Basically I will be acquiring data from flow meter, RTDs, TC and differential pressure transmitters. I want labview to calculate heat dissipation from this data.
I don't think this should be too much of a problem and labview will probably do a job.

but my question is about something else. I also have 2 readings from voltmeters. One is in the 0-40 V range and the other one is the range of 0 - 500 mA. Those values are respectively power supply voltage and shunt voltage (for high current calculation). For the same reason, I would be interested in getting an input device for these 2 measurements. I was wondering which hardware I need for that purpose. NI has some USB devices that would do this but it's limitated to -10/10V in general.

- what's best for the 0-40V range?
- what's best for low voltage measurement (0-1 V)?


thank you

[hoffiz]

Like you said most of our USB device will only handle from -10 to 10 volts. One of the suggestions I have for you is the NI-cDAQ 9221 (voltage 0 – 40 V). An excellent resource to look at is the USB-9201/9221 User Guide and Specifications.  To read current in this device you can make the current flow through a resistor and read the drop voltage from the resistor.  This module can be inserted in the cDAQ chassis or in theUSB-9162 carrier (see picture).

 

CDAQ-9219 is another module that will do both voltage and current readings but is not supported with the cDAQ-9162 (carrier) so you will need to get the chassis for this module; the current this can is handle 0-25mA. I will like to confirm that you meant 0-500mVolts not 0-500mAmperes. If you meant 0-500mA we don’t have a card that will handle this current (you will need to use a current divider)  if you meant 0-500mV then the 9219 is your best choice. A very good resource is also the NI Compact DAQ Advisor this will help you build your system.

Message Edited by Jaime F on 10-18-2007 08:58 PM