BharbourThe HP8116A function generator is a fairly old product. It is an analog function generator that HP added a GPIB interface to. It will output a range of 0.1mHZ to 50MHz with sine, square, pulse and triangle wave outputs. The instrument is old enough that the GPIB language is not SCPI, but R2D2. This tool will convert the R2D2 into human readable language. Read back capabilities are somewhat primitive.
Pretty much all of the GPIB commands listed in the Programmers Manual are supported. Commands can be supplied to the tool on the shell command line, from a script file, or from an internal shell-like mode. Arbitrary delays between commands can be set.
This tool shares the architecture of the project #HP E3634A Power Supply Control Software . Both tools share a lot of their source code. GPIB interface tasks are handled by the linux_gpib library that is available via Source Forge and other places. Linux_gpib supports many different interface boards and dongles. Development was done under Fedora 32 and tested on several other Fedora versions. You must install the linux_gpib package before building this tool.
Both the linux_gpib library and the National Instruments NI488-2 libraries are compatible with each other with minor exceptions. It is possible to build this package to run under Windows using the NI488-2 library. Instructions to do so can be found in my #HP545xx Data Acquisition Software project.
In order to build this project on a Linux machine, you must already have the linux_gpib package installed. There is a .h file needed at compile time and a library that is needed at link time for this package to compile successfully. Create a working directory to build the tool in and copy the .tgz file into it. Un-tar the file and type make:
> mkdir HP8116_ctl
> cd HP8116_ctl
> cp wherever/HP8116_ctl_xx_xx_xxxx.tgz .
> tar -xvf HP8116_ctl_xx_xx_xxxx.tgz
> make
and the software should build with no errors or warning messages. Finally, copy the executable program to a convenient directory in your executable path like ~/bin. There should be no need to do any of these tasks as root unless you want to put the executable in a directory off the /usr tree.
Typing ./HP8116_ctl with no parameters will give you a command listing:
Usage: HP8116_ctl [-d dev_addr] CMD1 [arg1] [CMD2]...
where CMDn [argn] is one of:
HELP cmd_name
READ_CMDFILE cmdfilename
INTERACTIVE [TOLERANT]
SLEEP_MS NmilliSeconds
DEV_CLR No Parameters
GET_STATUS No Parameters
GET_ERROR No Parameters
SET_TRIG_MODE NORM/TRIG/GATE/EXT_WID/INT_SWP/EXT_SWP/INT_BUR/EXT_BUR
SET_TRIG_CTL OFF/+/-
SET_MODULATION OFF/FM/AM/PWM/VCO
SET_WAVEFORM DC/SINE/TRIANGLE/SQUARE/PULSE
SET_START_PHASE 0/m90
SET_FREQUENCY freq.xx
SET_START_FREQUENCY start_freq.xx
SET_STOP_FREQUENCY stop_freq.xx
SET_MARKER_FREQUENCY marker_freq.xx
SET_DUTY_CYCLE duty_cycle [1..99]
SET_PULSE_WIDTH pulse_width [1nS..1.0S]
SET_REPEAT_INTERVAL repeat_interval [1nS..1.0S]
SET_SWEEP_TIME sweep_time [1mS..100.0S]
SET_BURST_COUNT burst_count
SET_AV_ENABLE ON/OFF
SET_AV MSB/MID/LSB UP/DN
SET_OUTPUT_LIMITS_ENABLE ON/OFF
SET_COMP_OUTPUT_ENABLE ON/OFF
SET_OUTPUT_ENABLE ON/OFF
SET_AMPLITUDE AMPLITUDE.xx
SET_OFFSET OFFSET.xx
SET_HI_LIMIT HI_LIMIT.xx
SET_LOW_LIMIT LOW_LIMIT.xx
GET_FREQUENCY No Parameters
GET_START_FREQUENCY No Parameters
GET_STOP_FREQUENCY No Parameters
GET_MARKER_FREQUENCY No Parameters
GET_PULSE_WIDTH No Parameters
GET_REPEAT_INTERVAL No Parameters
GET_SWEEP_TIME No Parameters
GET_DUTY_CYCLE No Parameters
GET_BURST_COUNT No Parameters
GET_AMPLITUDE No Parameters
GET_OFFSET No Parameters
GET_HI_LIMIT No Parameters
GET_LOW_LIMIT No Parameters
GET_CFG_DATA No Parameters
SHOW_RESPONSE Query_String
The configuration options (starting with -) must all be before the first command.
Commands may be entered in upper or lower case:
> SET_FREQUENCY 1.3e6
and
> set_frequency 1.3e6
issue exactly the same command to the function generator.
Instrument commands may be typed on the command line, like:
> HP8116_ctl SET_WAVEFORM SINE SET_FREQUENCY 2.5e3 SET_AMPLITUDE 0.707 SET_OUTPUT_ENABLE ON
to set the output frequency to 2.5KHz, set the amplitude to 0.707V and enable the output. Multiple commands can appear on a single line, separated by space characters.
Text command files can be used to run the same operations numerous times. After creating a text file hptest.txt containing:
SET_WAVEFORM SINE
SET_FREQUENCY 2.5e3
SET_AMPLITUDE 0.707
SET_OUTPUT_ENABLE ON
SLEEP_MS 500
SET_OUTPUT_ENABLE OFF
you can run that file:
> HP8116_ctl read_cmdfile hptest.txt
The interactive command reads commands as you type them and executes them after each line feed character. The biggest difference between using the command line method and the interactive method is that the GPIB bus does not disconnect between commands when using the interactive method, while it does disconnect between commands using the command line method.
Using the command line or the read_cmdfile methods will exit with an error if you fat finger a command or parameter. If the TOLERANT parameter in interactive mode is used, the program will not exit on parsing errors.
Also, when using the interactive mode, you don't have to type HP8116_ctl before commands.
One of the main uses for the interactive mode is when this program is exec'd from another program. Connecting to the stdin and stdout of this program in interactive mode allows full control from the calling program. The TOLERANT option will greatly simplify development of these applications.
A couple of debugging commands, SHOW_RESPONSE and SEND_CMD are included to allow sending a command to the 8116 and displaying the full response string, or just sending an arbitrary command.
The software is written in layers. The main function calls the parse_and_exec () function that parses the instrument commands. In the parse_and_exec.c file, the individual instrument commands get their parameters parsed and then call low level commands in HP8116A.c that assemble the outgoing strings, communicate with the GPIB driver and fetch results. The low level file (HP8116A.c and .h) could be used in a GUI driven program with the GUI software calling the low level command handling functions.