3. GENERAL OPERATION
Page 77
© 1998-2008 DH Instruments, a Fluke Company
REFERENCE
LEVEL
Reference
Line
(+)
(-)
The reference height of PG7000 pressure definition is the bottom of the piston in mid-
stroke float position. This position is marked on the piston-cylinder module mounting post and
on the optional AMH, mass automated handler. The DUT head height should be entered as a
positive value if the device or system under test is higher than the PG7000 reference level and
negative if it is lower.
To change units of DUT head height between inches and centimeters and to change the test
fluid, press [SPECIAL] and select <3Head> (see Section 3.11.3).
When the HEAD function is ON (DUT head value different from 0), the application of a head
correction is indicated by <h> in the right side of the top line of the MAIN run screen (see Section 3.7).
When the HEAD function is OFF, the <h> is NOT shown. PG7000’s also have a separate head
correction to compensate for the deviation between the current piston position and mid-stroke
(see Section 3.11.3.4). This PISTON head can be turned ON and OFF (see Section 3.11.3.4).
3.9.8
[ROTATE]
PURPOSE
To turn
automatic
control of motorized piston rotation (acceleration and brake) ON and OFF.
See Section 3.9.13 for information on manual control of motorized piston rotation.
Motorized rotation is optional in PG7102, PG7202 and PG7302.
PRINCIPLE
Motorized piston rotation is standard on PG7601 and optional on PG7102, PG7202 and
PG7302.
The motorized piston rotation system is used to start or increase piston rotation rate when the
piston is floating. It is also used to stop piston rotation when necessary, for example before
manipulating mass to set a new pressure. The system operates by engaging a motor driven
belt around the bottom of the mass loading bell to accelerate or brake the rotation rate of the
mass bell and piston it is loaded on. The motorized rotation system can engage with the
piston at any position in its stroke and at any rotation speed with minimal impact on piston
position and the defined pressure. When the motorized rotation system disengages, the
piston is completely free.