User`s manual

The Data Buffer Measurements are returned to the Data Buffer. The buffer is a
first-in-first-out (FIFO) buffer capable of storing 256 four-byte readings, or
up to 512 two-byte readings.
Address 151413121110 9 8 7 6 5 4 3 2 1 0
base + 0C
16
16-bit word
Four-Byte Reading
Mode
For aperture times of:
100 µs (opcode 05
16
)
2.5 ms (opcode 04
16
)
16.7 ms (opcode 01
16
)
20 ms (opcode 03
16
)
267 ms (opcode 00
16
)
320 ms (opcode 02
16
)
Each reading is a four-byte number arranged as follows:
Reading = effoprrr dddddddd dddddddd dddddddd
e = error bit. Set if an overrange, input overload, or sample rate
error occurs.
ff = function code (DCV, ACV, OHMS)
o = input overload bit. Set in conjunction with the error (e) bit. The
bit is cleared when a new range is set. (This also clears the NOERR
bit in the Status Register.)
p = sample rate overrun bit. Set in conjunction with the error (e) bit
when the sample rate is too fast for the specified aperture time.
(This also clears the NOERR bit in the Status Register.)
rrr = range code (power of 8 multiplier for reading).
dd = multimeter measurement in 2’s complement binary.
Readings are returned as two 16-bit words, with the upper word returned
first. Thus, for each reading, the data buffer must be read twice. The
“Programming Examples” section contains examples on retrieving
four-byte readings.
Two-Byte Reading
Mode
For the aperture time of:
10 µs (opcode 06
16
)
Each reading is a two-byte number arranged as follows:
Reading = dddddddd ddddddde
e = error bit. Set if an overrange, input overload, or sample rate
error occurs.
dd ... = multimeter measurement in 2’s complement binary.
Readings are returned as one 16-bit word. Thus, for each reading, the data
buffer is read once. The “Programming Examples” section contains
examples on retrieving two-byte readings.
208 HP E1326B/E1411B Multimeter Register-Based Programming Appendix C