DH Instruments PG7000, Руководство по эксплуатации и обслуживанию

Страница: 67 / 224

3. GENERAL OPERATION
Page 57 © 1998-2008 DH Instruments, a Fluke Company
Be sure the TEST BYPASS valve is in the OPEN position before adjusting the
static pressure. Failure to do so will cause differential pressure to be generated
across the HIGH and LOW TEST ports which may overpressure the DUT.
When the static pressure, as indicated
by the RPM, has been set to the desired
value, press
[ENTER] . PG7000 reads
the RPM and calculates the mass to load
on PG7000 to set the pressure value
indicated by the RPM. The display is:
Load mass & vac:
9.2 kg & 32.47 g
When using an AMH automated mass handler, the mass value to set the value
indicated by the RPM is always loaded with resolution of 0.1 kg. This is to avoid
having to break the reference vacuum to load trim masses. The differential pressure
values are loaded with the resolution specified in [RES] (see Section 3.9.10).
This is the standard nominal mass loading in instruction display of pressure to mass
mode (see Section 3.9.11.1). The mass loading instruction is always given with 0.01
g resolution regardless of the current mass loading resolution setting (see Section
3.9.10). Load the mass value following PG7000 mass loading protocol (see Section
3.6). If an AMH-38 automated mass handler is being used, the mass is loaded
automatically and default mass loading reasolution of 0.1 kg is used.
Set the PG7000 Differential Mode Controller (see Figure 9) to apply the pressure
defined by the PG7000 to the RPM (see Table 17).
Table 17. Valve Settings to Apply PG7000 Pressure
to the RPM for Differential Mode Offsetting
VALVE VALVE SETTING
Control Selection PG
PG Shutoff Open
Test Bypass Open
Static P Selection Off
If static pressure is atmospheric
pressure VENT or OFF
Once the valves have been properly set and the mass has been loaded, install
the bell jar and establish vacuum under the bell jar. Then press
[ENTER] .
The display is:
1. Current pressure reading of the RPM in the
current units of measure.
2. Standard main run screen piston position
indication (see Section 3.7).
3.
Current RPM offset (pressure applied by
PG7000 - RPM indication). Indicates
******* if the value is > 9999.99 Pa.
Pressure unit of measure is always
Pascal [Pa].
<<* 99.9785 kPa a h
-3.5 Off: -7.89 Pa