MKS Granville-Phillips 358 series, Instruction Manual

Page: 97 / 122

Operation
Series 358 Micro-Ion Controller Instruction Manual - 358013 - Rev. B
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7. Stable pressure measurement requires that all the environmental
parameters in, on, and around the vacuum gauge and vacuum system
remain unchanged during measurement. Therefore, never attempt
meaningful measurements immediately after turning on the Micro-Ion
Gauge or immediately after degassing the gauge. Permit sufficient time
for the environmental parameters to stabilize.
6.2 Micro-Ion Gauge ON/OFF
The Micro-Ion Gauge can be turned ON or OFF by the front panel GAUGE
“momentary” rocker switch or by the remote input, the Convectron Gauge
set point, or the computer interface command.
To turn ON the Micro-Ion Gauge from the front panel, press the GAUGE
momentary rocker switch. See Figure 6-2. To turn it OFF, press the GAUGE
rocker switch again. After a 3-second delay, the Micro-Ion Gauge pressure
will be displayed.
6.3 Degas ON/OFF
The EB (electron bombardment) degas may be turned ON or OFF by the
front panel DEGAS “momentary” rocker switch, (see Figure 6-2), or the
remote input. To turn degas ON, press the DEGAS momentary rocker
switch. To turn it OFF, press the DEGAS momentary rocker switch again.
Degas automatically turns OFF and returns to normal emission in 2 minutes.
Degas “ON” indication is by the degas LED adjacent to the DEGAS rocker
switch on the front panel (see Figure 6-2). Degas cannot be activated unless
the Micro-Ion Gauge has been turned ON and indicated system pressure is
below 5 x 10
–5
Torr. This prevents degas turn-on at pressures where
emission can not be established or where degas is of no practical use.
Micro-Ion Gauge pressure measurement is displayed during degas, but it is
not an accurate measurement during the degas cycle.
Table 6-1 Convectron Gauge Display Formats
Units Display Format Pressure Example
Torr scientific < 1 Torr 3.2–3 Torr
floating point > 1 Torr 7.1 Torr
mbar scientific < 1 mbar 5.1–2 mbar
scientific > 1 mbar 8.8+1 mbar
scientific > 999 mbar 1.2+3 mbar
pascal scientific < 1 pascal 7.2–1 pascal
scientific > 1 pascal 7.8+1 pascal
scientific > 999 pascal 1.2+4 pascal