DH Instruments ADCS-601, Руководство по эксплуатации и обслуживанию

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ADCS-601™ OPERATION AND MAINTENANCE MANUAL
© 2005 DH Instruments, Inc. Page 58
1. Piston position: For a Ready condition to exist, the PG7601’s piston must be
floating within the position limits defined in the PG7601’s active SETUP file
AND the PPC3 pressure controller is not controlling. The default PG7601
SETUP file is #2. The default piston position
Ready limits are - 2.5 mm and
+ 2.5 mm of midstroke. The full stroke of the piston from top stop to bottom
stop is + 4.5 to - 4.5 mm.
2. Piston rotation rate: For a Ready condition to exist, the PG7601’s piston
must be rotating at a rate within the rotation rate limits defined in the piston-
cylinder’s characteristics file. The default is 10 to 40 rpm. When the mass
load on the PG7601 is < 3 kg (corresponds to pressure of < 30 kPa (9 inHg))
the maximum rate limit is removed.
3. Reference vacuum level in absolute mode: In absolute measurement mode,
for a Ready condition to exist, the reference vacuum as measured by the
reference vacuum capacitance diaphragm gauge must be lower than the
vacuum limit specified in the PG7601’s active SETUP file. The SETUP file is
#2. The default minimum reference vacuum value is < 5 Pa (38 mTorr).
4.1.2.3 READY/NOT READY WHEN USING THE FPG8601 FORCE
BALANCED PISTON GAUGE
When the FPG8601 is the active pressure standard, ADCS-601 pressure
Ready/Not Ready depends upon the value and stability of the pressure
measured by the FPG8601 and the internal limits within FPG Tools . FPG8601
internal limits will force a Not Ready condition in the FPG8601 when ambient
conditions have significantly changed since the last FPG8601 zero. A feature in
the
[Maintenance] , [FPG Cal Options] menu is provided to decouple the
FPG8601 internal limits and the Ready/Not Ready status of the ADCS-601 when
the FPG8601 is the active reference (see Section 7.2).
When Regulation (see Section 4.1.4) is OFF, the ADCS-601 Ready/Not Ready
condition when using the FPG8601 is dependent on:
1. FPG8601 pressure stability: For a Ready condition to exist, the FPG8601’s
pressure rate of change must be less than the FPG8601 stability criterion.
The default FPG8601 stability criterion is ± 0.5 Pa/s (0.00015 inHg/s).
When Regulation (see Section 4.1.4) is ON, the ADCS-601 Ready/Not Ready
condition when using the FPG8601 depends upon:
1. FPG8601 pressure hold limit: For a Ready condition to exist, the pressure
measured by the FPG8601 must be inside of the FPG8601 pressure hold
limit. The default hold limit is ± 1.0 Pa (0.0003 inHg).
2. FPG8601 pressure stability: The FPG8601 pressure stability criterion is not
used to determine Ready when the ADCS-601 is actively controlling a
pressure. When pressure control is aborted, a Ready condition will occur
when the FPG8601’s pressure rate of change is less than the FPG8601
stability criterion.
4.1.3 TRANSITION BETWEEN STANDARDS, ACTIVE AND
INACTIVE STANDARD
The ADCS-601 system is made up of two automated pressure standards with overlapping
ranges to cover the full pressure range. An automated PG7601 piston gauge covers the
range of 15 to 380 kPa (4.5 to 120 inHg) (see Section 2.2.1). The PG7601 range is extended
down to 1 kPa (0.3 inHg) by an FPG8601 force balanced piston gauge with automated
pressure control (see Section 2.2.2).