Using
IEEE-488 Voltage Sources
Agilent
3631A
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
To control the voltage at the output of the power supply you need to do
the following.
-
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.
Here is a link to a LabVIEW vi that lets you type in a voltage and set
the power supply.
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.