You can program the Hydra in LabView  The specific LabView program here take a single DC voltage measurement.

Links to other Hydra notes.

Introduction to the Hydra

Manual Operation

Setting The Hydra And The Computer To Communicate

General Computer Operation

Commands For A Single DC Voltage Measurement

Programming The Hydra in C

Programming The Hydra In C++ (GUI/Visual Applications)

Programming The Hydra In Visual Basic

Programming The Hydra in LabView

    Given a Hydra and a Wintel computer,

    Be able to write LabView programs to measure DC voltages.

The Hydra should be turned on.

The Hydra and the computer should be set so that they can communcate.

        If you have taken care of all of the above, then you need to do the following.

• Establish a directory on your computer for your work.
• Copy a file into that directory.  That file is available in E. J. Mastascusa's public space on the network.  Here is the complete path:
• Network Neighborhood
           Entire Network
            Academic_depts
                mastascu
                    public
                        Labs
                            LabView
                                Hydra

    The file you need is:

Hydra2.vi

• Start LabView on your computer.
• Open Hydra2.vi.
• Examine the diagram by selecting Window - Show Diagram from the menu.  You should have the diagram shown below.

 

 
 




• Note the sequence of operations in the diagram flows from left to right in this particular diagram.  We did that deliberately so that we could show the flow of operation in the program.

        Note the following about this program.

The first operation is to write a string - *RST - to the Hydra.  The write operation is similar to ibwrt in other programming languages.  Here you use a GPIB Write block.

Note that you do not use the string "Hydra" to identify the Hydra in LabView.  Instead, you use the IEEE-488 address set on the Hydra.  That value is 3 and is set in the pink string constant.  Note that the blue numeric constant sets the mode so that a CR and LF are appended to the string when it is sent.

This program sends four strings/commands to the Hydra.  Click here for a quick review of the commands for a single DC voltage measurement.  The strings are:

*RST
FUNC 0,VDC,AUTO
*TRG
LAST?,0

To get the measurement into the computer, use the GPIB Read function.  Here the program allows for a 20 character string and when the string is read the string shows up in an output text box which can be seen on the panel view.

First, note that temperature cannot be measured from the front panel - Channel 0 -
 and you will have to use one of the other channels.

Here's a command string you can use.  This sets the Hydra for a temperature
 measurement.  Everything else can stay the same in the program.

FUNC 1,TEMP,K

This will measure TEMPerature using a type K thermocouple connected to Channel 1 on the connector strip cemented to the top of the Hydra DAU (See below.).  You cannot measure temperature using a thermocouple and the front panel connectors.