Keysight Technologies 3458A Guide D'utilisation page 163

Making Measurements 4
Fast FREQ (or PER) example
The following program measures frequency at a fast rate. This program can be
adapted to measure period by using the PER command instead of the FREQ
command in line 40.
10 OUTPUT 722;"PRESET FAST"!TARM SYN, TRIG AUTO
20 OUTPUT 722;"MFORMAT SREAL"!SINGLE REAL MEMORY FORMAT
30 OUTPUT 722;"MEM FIFO"!ENABLE READING MEMORY, FIFO MODE
40 OUTPUT 722;"FREQ 10, .1"!FREQUENCY, 10 V RANGE, 100 µs GATE TIME
50 OUTPUT 722;"ACBAND 10E3,20E3"!SIGNAL BETWEEN 10 kHz AND 20 kHz
60 OUTPUT 722;"NRDGS 100, AUTO"!100 READINGS/TRIGGER, AUTO SAMPLE EVENT
70 OUTPUT 722;"TARM SGL"!TRIGGER READINGS
80 END
High-speed transfer across GPIB
Configuring the output format (OFORMAT command) to match the format used by
the A/D converter (either SINT or DINT) ensures the fastest. transfer of readings to
the controller. This is because no format conversion is required in the multimeter.
For high-speed, low-resolution readings (3.5 or 4.5 digits) made on a fixed range,
use the SINT output format. (Because the SINT format uses only 2 bytes per
reading, multiple readings can be transferred across the bus faster using the SINT
output format than any other format.) For the fastest transfer of high resolution
readings (5.5 digits or greater) made on a fixed range, use the DINT output
format.
The multimeter is capable of taking readings and outputting them to the
controller at >100k readings per second. Using the SINT output format at this
reading rate, the GPIB and controller must be able to transfer data at >200k bytes
per second. For Hewlett-Packard Series 200/300 Computers, this requires a direct
memory access (DMA) card. In addition, devices that slow the operation of the
GPIB bus and any unnecessary lengths of GPIB cable must be removed to achieve
maximum transfer rate.
The following program transfers readings directly to the controller at the fastest
possible rate. This program configures the multimeter to take readings at its
maximum rate of >100k readings per second. Readings are output using the SINT
format. If the bus/controller cannot transfer readings at >200k bytes per second,
the reading rate will be slower.This is because, in the high-speed mode, the
multimeter waits until each reading is removed from its output buffer before
placing the next reading in the output buffer. In the following program, the SYN
Keysight 3458A User's Guide 163