Fluke PM6685R, PM6681R manual Time Stamp Readout Format, Format Subsystem

Using the Subsystems

Format Subsystem

Time Stamp Readout Format

It is not trivial to decide how time stamped measurements are to be pre- sented on the bus. If the ‘ADIF’ format defined by SCPI is adopted, it should be adopted for all data readout, and switched on and off by the already standardized :FORMat:DINTerchange command. This format covers the appropriate readout for- mat for time stamped measurements well, so when it is selected as output format, there is not any problem. But the user may still decide not to use the ADIF for- mat, so we need a solution to the readout problem whether or not we decide to im- plement ADIF. The chosen one is as fol- lows:

For :FETCh:SCALar?, :READ:SCALar? and :MEASure:SCALar?, the readout will consist of two values instead of one.

The first will be the measured value, and the next one will be the timestamp value, given in seconds in the NR2 format ddd.ddddddddd (12 digits).

In :FORMat ASCii mode, the result will be given as a floating-point number (NR3 format) followed by integers (NR1 for- mat). In :FORMat REAL mode, the result will be given as an eight-byte block con- taining the floating-point measured value, followed by a four-byte block containing the integer timestamp count, where each count represents 125 nanoseconds.

When doing readouts in array form, with :FETCh :ARRay?, :READ :ARRay? or :MEASure :ARRay?, the response will consist of alternating measurement values and timestamp values, formatted the same way as for scalar readout. All values will be separated by commas.

6-6 Format Subsystem