DH Instruments ADCS-601, Руководство по эксплуатации и обслуживанию

Страница: 148 / 174

ADCS-601™ OPERATION AND MAINTENANCE MANUAL
© 2005 DH Instruments, Inc. Page 136
Table 21 . Metrological maintenance procedures
SYSTEM PROCEDURE DESCRIPTION FREQUENCY SEE
SECTION
FPG8601 Zero load cell Fully automated routine that corrects
zero drift of the load cell. Set to perform automatically by ADCS
Tools each time the FPG8601 is used.
After measurement mode (gauge,
absolute) change; at the start of a test;
when recommended by FPG
Validation
7.2.2
FPG8601 Calibrate load
cell span
Fully automated routine that calibrates
the span of the load cell using an
FPG8601 on-board reference mass.
Set to perform automatically by ADCS
Tools when FPG8601 is used. If
recommended by validation with
PG7601
7.2.2
FPG8601 Validate with
PG7601
Fully automated routine that compares
the FPG8601 to the PG7601 to verify the
FPG8601.
Weekly; after calibration of PG7601;
after repair/calibration of FPG8601
7.2.3
FPG8601 Check on-board
P, T, H values
Verification that FPG8601 lubrication
pressure, temperature and humidity
sensors and piston-cylinder temperature
values are within expected range. Weekly; If recommended by validation
with PG7601 7.2.3.3
FPG8601 Validate load cell
linearity Verification of load cell linearity by
loading it with calibrated masses. If recommended by validation with
PG7601 7.2.5
FPG8601,
PG7601 Zero reference
vacuum CDGs Mount CDGs directly on reference
vacuum cross, pull down to hard
vacuum, compare to a reference (ion
gauge) and adjust zero reading as
needed. Monthly until decreased frequency
justified by experience 7.2.6
PG7601 Adjust on-board
P, T, H sensors Verify PG7601 Platform ambient
pressure, temperature and humidity
sensor readings relative to a standard
and adjust if necessary. 6 months, increase to 1 year when
justified by experience 7.2.7
7.2.2 FPG8601, ZERO AND ADJUST SPAN OF LOAD CELL
The FPG8601 uses a precision load cell to measure the force resulting from the pressure
across its piston-cylinder. The load cell zero may drift with time and ambient condition
changes. The span also may drift, but to a much lesser extent. For this reason, it is
necessary to zero and span the load cell regularly. Since the zeroing and span adjustment of
the load cell can be performed automatically by the system, transparently to the operator,
they do not normally require any special scheduling or procedure (see Section 7.2.2.1). If
desired they may also be initiated by the operator (see Section 7.2.2.2).
For additional information on the FPG8601 load cell and the load cell zeroing and
spanning functions, see the FPG8601 Operation and Maintenance Manual.
7.2.2.1 AUTOMATICALLY INITIATED LOAD CELL ZERO AND SPAN
ADJUSTMENT
ACDS Tools can be set to zero and adjust the span of the FPG8601 load cell
automatically as part of regular ADCS-601 operation. This is the default setting
and recommended procedure.
ADCS Tools , [Maintenance] , [FPG Cal Options] provides options concerning
when the FPG8601 load cell should be zeroed and spanned automatically. The
default is for the process to occur prior to use each time the FPG8601 is
activated. This assures that the FPG8601 load cell is always properly adjusted
before it is used but it adds 40 to 60 seconds to the first pressure point
performed with the FPG8601. To avoid this delay, if the FPG8601 is used
regularly, change the
[Maintenance] , [FPG Cal Options] to <Zero FPG when
isolated> , keeping <Run FPG internal calibration on each FPG zero> .