PG7000™ OPERATION AND MAINTENANCE MANUAL
© 1998-2008 DH Instruments, a Fluke Company
Page 78
With automatic motorized rotation ON
, the motorized rotation system engages and
disengages automatically as needed when the piston is floating to maintain the piston
rotation rate above the minimum rate
Ready
limit (see Section 3.4.2). The rotation rate is
measured by PG7000 on board sensors and the rotation rate limits are set in the file of the
active piston cylinder (see Section 3.11.1.1). Whenever the piston is floating, the motorized
rotation system will attempt to maintain the piston rotation rate within the
Ready
limits (except
under the cutoff mass load of 3 kg, at which the low limit is reduced to minimum to maximize
free rotation time. The piston rotation
Ready/Not Ready
indication character indicates
Not
Ready
to alert the operator when the motorized rotation system is about to engage. The
rotation system will not engage when the current mass load is less than the mass of the
mass loading bell.
The motorized rotation system is also used to brake and stop rotation when starting a new
pressure point. If the piston is floating and rotating when
[ENTER/SET P]
is pressed, the
motorized rotation system engages at a speed near the rotation rate of the piston and then
brakes it to a stop. Piston rotation is stopped to avoid loading and unloading masses on the
rotating piston and to avoid stopping rotation by friction between the piston and the piston
end of stroke stops.
With automatic motorized rotation OFF
, the motorized rotation system engages only when
actuated by the operator. Pressing
[
]
accelerates rotation or
[
]
followed by
[
←
]
stops
rotation (see Section 3.9.13).
Automatic motorized rotation is generally left ON for normal operation. It is turned OFF in
situations where rotation system actuation independent of operator initiative is undesired
(e.g. when performing a crossfloat intercomparison with another piston gauge).
OPERATION
To access the AutoRotate functions, press
[ROTATE]
. The display is:
AutoRotate OFF
1on 2pre-decel
<AutoRotate ON>
or
<AutoRotate OFF>
indicates the current state of AutoRotate. Use
<1on>
or
<1off>
to change the state.
If PG7000 is NOT equipped with motorized rotation,
<Automatic rotation not available>
is
displayed momentarily when
[ROTATE]
is pressed.
When automated rotation is OFF, the PG7000 motorized rotation system will only engage if
the operator presses
[
]
or
[
]
followed by
[
←
]
(see Section 3.9.13).
When automated rotation is ON, the automated rotation system engages automatically.
When the piston is floating, it engages as needed to maintain the piston rotation rate above
the
Ready
limit (see Section 3.4.2). When
[ENTER/SET P]
is pressed, it engages to stop
rotation before masses are loaded and/or the pressure is adjusted (this function can be
turned ON and OFF, see Section 3.9.8.1). Manual control using
[
]
and
[
]
followed by
[
←
]
is also still active.
Automatic motorized piston rotation is dependent on PG7000’s measurements of piston
position and rotation rate. These measurements are only available when the mass loading bell is
installed on the piston. Automatic piston rotation is suspended when the current PG7000 mass
load does not include the mass loading bell.
Proper operation of the rotation system is dependent on PG7000’s measurements of
piston position. When using AutoGen, be sure that the piston position indication system is
properly adjusted (see Section 5.2.2).
