A Note on Using the 3631A Triple Output Power Supply

The Agilent 3631A

        The Agilient 3631A is a triple output power supply.  The voltage outputs are:

• 0 to 6v

• 0 to 25v

• 0 to -25v

• Select which voltage output you want.  (6v, 25v, or -25v - there are 3 different supplies in a single instrument.)

• The GPIB/IEEE-488 commands you need to use are as follows.

  • *RST - which resets the power supply.

  • INST P6 - which selects the 6 volts supply.  The "P" indicates this is a positive supply.

  • VOLT x.yy - which sets the output voltage that will appear at the terminals of the supply.

  • OUTP:STAT ON - which sets the status of the supply to ON.

Some Questions Regarding the Voltage Output

• In typing in the voltage, you have two choices.

  • You can use a text string.

    • The text string can be a constant - if you want a constant voltage.

    • The text string can be generated using a text input box (a text control).

  • You can use a numerical value.

    • The numerical value can be a constant - if you want a constant voltage.

    • The numerical value can be generated using a numerical control.

    • The numerical value could be generated within a program as a reslt of a calculation within the program.

    • If a numerical value is used, the numerical value has to be converted to a text string in order to send the proper text string to the instrument.  The converted value has to be concatenated with the rest of the command string to produce something like VOLT x.yy in order to make the instrument actually produce the voltage.  You have to produce the string x.yy.

  • Which would you choose to do?  Would you use a string or a numerical value?  The answer to that depends upon what you are building to.  If you only want to produce a voltage once, just to demonstrate that you can, go ahead use a text string.  But, if you want to end up with a program where the voltage is computed, then you will have to deal with a computed numerical value, and you will have to do the text manipulation.

  • One final note.  If you use the 3631A to produce a voltage you only need to write commands to the instrument.  You will not need to use a GPIBRead block on your block diagram because you never need to transmit information from the instrument to the computer.  The only exception to this is if you actually use the 3631A to monitor its own terminal voltage (which is possible, but not often done) and you want to know what the terminal voltage is.