DH Instruments PPCK PLUS, Operation And Maintenance Manual

Page: 60 / 150

PPCK+™ Operation and Maintenance Manual
©2001 DH Instruments, Inc .
Page 52
If the measurement mode of the current range is absolute the display is:
1. Current range.
2. Current measurement mode.
3. Selection of source of ZSTD for ZOFFSET
determination.
Selecting <1Entry> allows the value of ZSTD to be entered from the front
panel keypad.
Selecting <2COM2> allows the value of ZSTD to be read automatically from an RPM
interfaced with PPCK+'s COM2 communications port.
Allow the PPCK+ to stabilize at atmospheric pressure and ambient temperature for
5 to 10 minutes before running AutoZ.
If running AutoZ results in values of ZOFFSET that are greater than ± 0.015 % FS of
the current PPCK+ measurement range, the PPCK+ and/or the source of ZSTD may be
out of tolerance or the AutoZ process may have been faulty. Before activating a new
ZOFFSET greater than
±
0.015 % FS of the current PPCK+ range, check to be sure
that both the PPCK+ and the source of ZSTD were in good working order, properly
vented to stable atmospheric pressure, at the same height, and reading in the same
pressure units when AutoZ was run.
When the run AutoZ selection is made, if a HEAD correction is currently active
(see Section 3.2.7) the head correction will be disabled to avoid "autozeroing" the
head value.
The value of ZOFFSET in absolute mode will not be exactly equal to the difference
between the current reading and ZSTD if ZNATERR is not zero (see Section 3.4.1,
PRINCIPLE, How AutoZ Works).
The value of ZOFFSET is always displayed and entered in Pascal (Pa).
AutoZ H3 abs by:
1Entry 2COM2