2. PREPARATION FOR OPERATION
2.3.2.6
CONNECTING AN EXTERNAL REFERENCE VACUUM
GAUGE (AMH-38 ONLY)
The AMH-38 vacuum chamber is equipped with two KF-40 vacuum connections.
One of these may be used to connect an external vacuum gauge as an alternate
to the vacuum gauge built-in to the PG7601 platform. This may be desirable to
measure the reference vacuum with lower measurement uncertainty that the
PG7601’s internal vacuum gauge.
See the PG7000 Operation and Maintenance Manual for information on using an
external vacuum gauge to measure reference vacuum pressure.
2.4
PREPARING THE PG7000 PLATFORM
2.4.1
PREPARING PG7102, PG7202, PG7302 PLATFORM
HARDWARE FOR AMH-100
Most PG7102, PG7202 and PG7302 Platforms delivered after 2004, January 1, are AMH
ready. AMH ready platforms have three machined holes in the top surface of the base
casting to seat the AMH-100 legs.
To prepare the AMH ready platform, loosen the three set screws on the sides of the base
casting until the screw is just past flush with the side (2.5 mm allen wrench). Remove the
two black plastic caps and the bubble level assembly, exposing the AMH-100 seating holes.
When AMH-100 is used, the bubble level on the AMH-100 center plate is used to level the
PG7000 system. Retain the casting level in case of future use of the platform without the
AMH accessory.
If your PG7102, PG7202 or PG7302 does not have the three AMH leg holes on the top
surface, the based casting must be replaced before AMH can be used with the platform.
Contact
DHI
or your local
DHI
representative.
2.4.2
PREPARING PG7601 PLATFORM HARDWARE FOR AMH-38
Most PG7601 platforms with a serial number higher than 124 are AMH ready. Serial
numbers 124 and lower (units delivered prior to 1994) may require a new vacuum plate. To
determine if a PG7601 vacuum plate is AMH ready, measure the width of the flat horizontal
surface from the outermost diameter of the plate to the inner chamfer. (see Figure 3) If this
width is 12.2 mm, the vacuum plate will accept AMH; if the width is 7.2 mm, the vacuum
place must be replaced. Contact a DHI Authorized Service Provider.
F ig u re 1 .
P G 7 6 0 1 V a c u u m P la te D e t a il
F ig u re 2 .
P G 7 6 0 1 V a c u u m P la te D e t a il
F ig u re 3 .
P G 7 6 0 1 V a c u u m P la te D e t a il
F ig u re 4 .
P G 7 6 0 1 V a c u u m P la te D e t a il
F ig u re 5 .
P G 7 6 0 1 V a c u u m P la te D e t a il
F ig u re 6 .
P G 7 6 0 1 V a c u u m P la te D e t a il
F ig u re 7 .
P G 7 6 0 1 V a c u u m P la te D e t
The vacuum plate of an AMH ready PG7601 must be inspected for damage prior to
attempting to install AMH-38. The AMH-38 vacuum chamber fits over the outside diameter of
the vacuum plate. Displaced material from
dents or dings on the outside corner of the
plate could increase the effective diameter
making it difficult or impossible for the
AMH-38 vacuum chamber to fit over the
plate. Inspect the outside diameter of the
vacuum plate (see Figure 3). Remove any
material on the outside surface and return
to a finish of approximately 0.8
micrometers or better. If you are not
comfortable performing this task with in-
house capabilities, contact an Authorized
DHI Service Provider.
Figure 3
. PG7601 Vacuum Plate Detail
Page 13
© 2007 DH Instruments, a Fluke Company
