Created on 2009-06-08 18:03:00

Question:
I am having a problem programming the Audio PrecisionPortable One with direct I/O over GPIB using HPVEE. The read command “M1?”gives a timeout error. Please give me a sample HPVEE program to illustratereading the measured input voltage on the Portable One.

Answer:
At AP, we do not use, nor do we support the HP (now Agilent)VEE programming language. However, controlling an instrument over GPIBessentially involves writing command strings to the instrument and reading itsresponse strings. As long as the command strings have the correct syntax andare in the right sequence, your GPIB program should work properly, regardlessof which programming language you are using.

The Audio Precision GPIB Talker Listener Utility (available inthe 2700 Programmer’s Starter Kit 2700-PROG) is a great tool for debuggingGPIB instrument communication issues. Although developed for the 2700 Seriesanalyzers, this utility works with all Audio Precision GPIB equippedinstruments. The utility simplifies communication with GPIB instruments andprovides a convenient Windows interface that makes it simple to send commandsto an instrument and read back the instrument response.

Figures 1 and 2 below are screen shots that illustratesending the following commands to the Portable One:

*CLS;                                           ‘clearstatus
INPUT GAGB;                             ‘set the inputs toGenerator A and Generator B
OUTPUT
ON;                                               ‘turn on thegenerator
GAMPLITUDE-10 DBV;              ‘set the amplitudeto -10 dBV
GFREQUENCY 500 HZ;              ‘set the frequencyto 500 Hz
FUNCTION LEVEL;                    ‘select the Levelfunction
SETTLE ON;                                 ‘turn on settling
*CLS;                                            ‘clearstatus
M1?;                                              ‘readmain meter (left meter on front panel)
M2?;                                              ‘readsecondary meter (right)

Figure 1. The GPIB Talker Listener Utility.

Figure 2. Sending a string greater than 255 characters long.

The Portable One’s response to the M1? and M2? commands isshown in Figure 3.

Figure 3 Response to the M1?; M2? Commands (A = 313.3 mV, B = 316.2 mV).

If you don’t have access to the Audio Precision GPIB TalkerListener Utility, there may be a similar utility bundled with the GPIBinterface used in your PC. For example, the Measurement and Automation Explorersoftware, which comes with National Instruments GPIB interfaces, includes autility to send and read strings from GPIB devices.

slx 4040
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