HP 3468A - Receiving Measurement Data; HP-IL Interface Control Operations

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Not only can the 3468A be controlled by the -hp- Model 41C/41CV calculator,
but it can also talk to the calculator. The calculator can then process the measure-
ment data or status information as necessary.
From the last section we saw how to program the 3468A to take one ac voltage
reading on the 300mV range. Now let’s see how to transfer the measurement
from the 3468A to the calculator.
Keystrokes Display
XEQ} [ALPHA] IND [ALPHA]
XEQ IND
That is all there is to it. The measurement will appear in the calculator’s display as
well as in the X-register. Since the reading is in the X-register it is ready to be
operated on by the calculator. You could take the log of the reading by pressing
the LOG key for example. IND (INput Decimal) is an instruction that causes the
3468A to talk (TLK annunciator) to the calculator, giving it the measurement data.
If you look closely at what we have done, we have actually written a very simple
program. The program instructs the 3468A to take a particular type of measure-
ment and send the measurement results to the calculator. Later, you'll learn to
complete the program by adding a label and an END or return statement. Look at
the listing below and compare it to the instructions previously executed.
GLoLBL “ACYOLTS*
G2 “FeRIRAZIN4T2°
83 OUTA
44 IND
85 END
HP-IL Interface Control
Before pursuing further the subject of program writing, let's look at some special
HP-IL commands. In the examples we've looked at so far, commands like IND,
OUTA, or REMOTE were used. These commands are called Interface Control
Operations. Now you'll learn what these and other operations mean and how they
are used. The control operations allow you to directly specify a device to perform
a function, send or receive information, or control the interface loop. These control
operations also allow more than one 3468A to be used in the loop along with
almost any other HP-IL device.
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