PG7000™ OPERATION AND MAINTENANCE MANUAL
© 1998-2008 DH Instruments, a Fluke Company
Page 180
To adjust the PG7000 piston position system when an AMH mass set is being used, proceed
as follows:
Vent
pressure.
Select
[SPECIAL]
,
<8AMH>
, .
<2control>
,
<2discreet>
and load all of the binary
masses and none of the main masses (see Section 3.11.8.2).
Press
[SPECIAL]
,
<7cal>
,
<5Pposition>
,
<2cal>
.
The
prompt
<Hold piston at max down stop>
appears. Check that the pressure under
the piston is really vented and press
[ENTER]
.
The
prompt
<Hold piston at max up stop>
appears. Without changing the mass load,
generate a pressure under the piston great enough to insure that the piston will go
completely to the top stop. This requires a pressure equivalent to a mass load of 18 kg
with an AMH-100 or 12 kg with an AMH-38. For example, if the mass handler is an
AMH-100 and the piston is a 2 MPa/kg, generate 36 MPa or if the mass handler is an
AMH-38 and the piston is a 10 kPa/kg, generate 120 kPa. Press
[ENTER].
Process is complete. Use
[SPECIAL]
, select
<7cal>
,
<5Pposition>
,
<1view>
to verify
that piston position is
<+4.5 mm>
when fully up and
<-4.5 mm>
when fully down.
5.2.3
EMPTYING OIL RUN-OFF TRAY (PG7202 AND PG7302 ONLY)
In PG7302, small quantities of oil escape from beneath the piston-cylinder during the air
purge process when installing a piston-cylinder module (see Section 2.3.2). In both PG7202
and PG7302, very small quantities of oil leak out of the top of the gap between the piston and
cylinder when pressure is applied.
Excess oil is collected and runs down the mounting post, and out through a transparent tube
on the right side of the PG7202/PG7302 Platform to an oil run-off tray under the platform.
To empty the oil run-off tray, proceed as follows:
Using a paper towel or cloth to catch oil drops, gently pull the transparent tube out of the
oil run-off tray.
Grasp the run-off tray by its protruding handle and slide it completely out and away from
the PG7202/PG7302 Platform.
Empty the oil run-off tray by shaking it out or removing the screws on the top plate.
Clean the oil run-off tray. Discard any accumulated oil.
Slide the oil run-off tray back into the PG7202/PG7302 Platform. Push it in beyond the
holding stops until it seats firmly.
Reinsert the transparent oil run-off tube into the hole in the run-off tray handle.
5.2.4
PURGE MOUNTING POST LIQUID RUN OFF (PG7202 ONLY)
In PG7202, minute quantities of the liquid that lubricates the gap between the piston and the
cylinder flow out of the bottom of the gap. A passage in the mounting post (see Figure 13),
channels this liquid directly to a low point drain. A DRAIN port on the rear of the PG7202
Platform (see Figure 3) allows the drain to be purged. The drain should be purged
approximately once a day when PG7202 is being used extensively or before using PG7202
any time it has been idle with a piston-cylinder module installed for an extended period.
