HP 3468A - Page 37

Let's take a close look at what we did. First, the Alpha register in the calculator
was cleared with the correction key (left arrow) and then, the message ”“D2YOUR
NAME” was put into the Alpha register. D2 is called the command code and tells
the 3468A that the message following it is to be displayed. Second, the com-
mand OUTA (OUTput Alpha register) was executed (XEQ). Since the 3468A was
the selected device, it received the instruction.
There are several command codes that the 3468A recognizes and responds to.
The blue page at the end of this chapter shows the command codes, what they
mean and valid combinations of Function and Range codes. A list of command
codes is also located on the underside of the 3468A. Command codes may be
combined to form a string of commands so that all are sent at one time.
For example, to take the 3468A out of the display message mode, send the com-
mand D1 (Display 1). After displaying a message, if D1 is not sent, the 3468A
continues to display the message sent to it. The command code for the 2-wire
ohms mode is F3 (Function 3). To set the 3468A to the 2-wire ohms mode, load
the calculator Alpha register with the code F3 and execute the OUTA instruction.
To set the multimeter to the 3 Kohm range use the command R2. The three com-
mands can be combined in the alpha register and sent to the 3468A:
FSR2
OUTA
Sample Problem
Suppose you need to make an ac voltage measurement that is known to be be-
tween .20 volts and 1.0 volt. You also want the Autozero feature on and the
measurement to be made in the 4 1/2 digit mode. What series of instructions will
accomplish this?
First, it is an ac voltage measurement, therefore use code F2. You don’t know
whether to use the 300mV range or the 3 Volt range, so use Autorange, com-
mand RA. The instruction for autozero on is Z1, and for the 4 1/2 digit mode, N4.
The command string now looks like:
“F2 RA Z1 N4”
Since you know the voltage to be measured is small, set the 3468A to a low
range before it autoranges. The command R1 will do this. Furthermore, if you
want the meter to take only one reading, add the instruction T2 to the end of the
string. By adding it at the end, the meter is setup for the measurement before be-
ing triggered. The complete string now looks like this:
“F2 R1 RA Z1 N4 T2”
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