Sending A Remote Command
To send the Electronic Load a remote command, combine your computer’s output statement with the GPIB interface select code, the GPIB device (Electronic Load) address, and finally the Electronic Load’s HPSL command. For example, to set the input current of a previously specified channel to 10 amps, send:
Getting Data Back
The Electronic Load is capable of reading back the values of parameter settings as well as its actual input voltage and current or computed input power. It can also return information relating to its internal operation and instrument identification. In order to read back the desired information, you must send the appropriate query to the Electronic Load. For example, the query "MEAS:CURR?" asks the Electronic Load to measure the actual input current at the INPUT binding posts. Refer to the Agilent Electronic Loads Programming Reference Guide for complete details on using queries.
The Electronic Load stores its response to the query in an output buffer which will hold the information until it is read by the computer or is replaced with new information.
Use your computer's enter statement to read the response from the Electronic Load’s output buffer. The following example asks the Electronic Load its actual input current and then reads the response back to the computer.
10 OUTPUT 705; "MEAS:CURR?"
20 ENTER 705; A
30 DISP A
40 END
Line 10: Measures the actual input current.
Line 20: Reads the actual input current level back into variable A in the computer.
Line 30: Displays the input current value on the computer's display
Remote Programming Commands
The Electronic Load command set consists of more than 60 HPSL compatible commands. The HPSL commands have many optional key words which can be used to document your programs. Most of the commands have a query syntax which allows the present parameter settings to be read back to the controller. All of these details are given in the Agilent Electronic Loads Programming Reference Guide .
The Electronic Load's major functions can be programmed using a relatively few number of these commands. Figure
The remaining paragraphs in this chapter give a few simple programming examples to help you get started. In each example, it is assumed that a dc power source is connected to the Electronic Load’s input binding posts. Also, the following points are important to remember when you are remotely programming current, resistance and voltage values.