labVIEW with Multisim

[M Adnan Younus]

Dear sir

is it posible to convert labview (tharmal sensor.vi) file into multisim (tharmal sensor.ms10) for auto simulation ? 

[_user32]

M Adnan Younus,

Yes, depending on what you are trying to accomplish... let me explain.

If you have a VI that programmatically converts physical units (such as temp) to voltage than yes, this will give you the correct behavior.   To create one yourself, follow this guide:

http://zone.ni.com/devzone/cda/tut/p/id/5635

Attached, is one that I've previously created for a thermocouple allowing you to set type / and the range on the thermocouple (using an existing VI that converts TC temp to TC voltage) and ramps the output across a temperature range / time duration that you specify...

Regards,

Patrick Noonan
Business Development Manager
National Instruments - Electronics Workbench Group

[place attached .llb in /lvinstrument folder under Multisim 11 installation folder]

(This LabVIEW instrument was created for and tested with Multisim v11)

[RadioRanger]

Patrick

I tried your ThermocoupleSource.llb.  However, as a test I connected it to a multimeter, set to K type and Temp from 0 to 100 .  When it reached 100 degree,  the multimeter indicated 3.682 mV instead of the 4.1mV that I expected.  What am I doing wrong?

Joe Kuran

[_user32]

Joe,

I tried it and it looks correct.   A couple of things - did you try it without the ramp?  Just set it at 100 degC (uncheck the ramp button) and see if it comes out at 4.092V?

Second thing - perhaps its switching back to 0 degC quickly and not hitting the final value on the Multimeter - in the VI there is a 'Repeat Data' check box - try unchecking that and the last reading should hold for you at the 100 degC value.

If you still cannot get this to work, try looking at your Multimeter settings (Set... button and then look at Voltmeter resistance) - there may be some issues with the default settings (although mine are set fine).

Regards,

Pat

[RadioRanger]

Pat

That does it. Thanks.

Joe

[RadioRanger]

Pat

I am using a circuit from the AD8551 Data sheet for this thermocouple. It uses a isolated ground.  Can this instrutment be modified for this?  I attached file,

Joe

[_user32]

Joe,

Hello - at the current time, it may be hard to modify this LabVIEW Instrument source to have a floating ground (as our source instruments do not have the ability to add a SPICE model pin at the output - BTW, our input LV instruments do have this ability). 

However you can use a controlled 'E' source (Voltage Controlled Voltage Source) to buffer the LabVIEW instrument output to the circuit to accomplish the same thing - essentially giving you a differential output that can be referenced to an isolated (i.e. floating) node.

This source (VCVS or 'E' source) is located here in the Master DB:

Sources -> CONTROLLED_VOLTAGE_SOURCES -> VOLTAGE_CONTROLLED_VOLTAGE_SOURCE

I'll leave the implemenation as an exercise to the user...

Regards,

Pat Noonan

National Instruments