Reading Rates; Ranges - Fluke 8845A Manual

8845A/8846A
Programmers Manual
Primary
Functions
VDC
VAC
IDC
IAC
FREQ
OHMS
DIODE
Continity

Reading Rates

Like the 884XA meters, the Fluke 45 has multiple but different reading rates. The reading
rates for the 884XA meters are based on the Number of Power Line Cycles (NPLC),
which are explained in the Users Manual. The Fluke 45, on the other hand, has just three
reading rates, selected as Fast, Medium, and Slow. To be compatible with Fluke 45 code,
the 884XA meters will use a reading rate of 2.5, 5, and 20 readings per second,
respectively.

Ranges

The Fluke 45 changes range at different points than the 884XA. For example, the 884XA
dc voltage range changes occur at 120 mV, 1.2 V, 12 V, and 120 V. The Fluke 45 on the
other hand, changes ranges at the same points when it is in Slow resolution, but for
Medium and High resolution, changes occur at 300 mV, 3 V, 30 V, and 300 V.
The 884XA meters will respond to a range query with the expected Fluke 45 range
whenever the range has previously been set by a range set command. However, when the
884XA meters are set to VDC, VAC or OHMS with autorange enabled and measuring
with Medium or High resolution, the range returned to a range query command may
return a range value that is higher or lower by one range.
For the frequency function, the 884XA meters have one range: 3 Hz. The Fluke 45 has
five ranges. If the 884XA meters are sent a range set command, they will respond to a
range query with the set range value. If the frequency function is in autorange, however
the 884XA meters will respond with the value of zero.
The Fluke 45 allows range selection in CONTINUITY and DIODE TEST. The 884XA
meters have only one range for these functions. Therefore, whenever a RANGE
command is detected in the Fluke 45 emulation mode, the 884XA meters will respond
with an error.
104
Table 37. Fluke 45 Dual Function Compatibility Matrix
VDC VAC IDC
No Yes No
Yes No No
No No No
No No Yes
No No No
No No No
No No No
No No No
Secondary Function
IAC FREQ OHMS
No No No
No Yes No
Yes No No
No Yes No
No No No
No No No
No No No
No Yes No
DIODE Period RTD
No No No
No No No
No No No
No No No
No Yes No
No No Yes
No No No
No No No