To Next Page

To Previous Page

Chapter 3

30 Micro-Ion

Module Instruction Manual - 356007-GP

Figure 3-3 Gauge LED

Automatic Filament

Selection

As the vacuum system pumps down from atmosphere, the Conductron

sensor measures pressure until a pressure of 20 mTorr (2.66 x 10

–2

mbar,

2.66 pascal) is achieved, then automatically turns ON the Micro-Ion gauge.

Tungsten filaments are more likely than yttria-coated iridium filaments to

burn out if they turn ON at a pressure that is too high. To reduce the risk of

burnout, the default behavior of the Micro-Ion gauge depends on the

filament material.

If a rapid increase in pressure from high vacuum levels to pressures of 1 Torr

(1.33 mbar, 133 pascal) or higher pressure occurs, tungsten filaments are

almost certain to burn out. This risk is not unique to the Micro-Ion gauge

and exists for all ion gauges with tungsten filaments.

The catalog number on the Micro-Ion Plus Module will indicate whether

your module has yttria-coated iridium filaments or tungsten filaments.

• 356xxx -Y-x-x : Y = Yttria coated iridium

• 356xxx-T-x-x : T = Tungsten

Table 3-2 lists default delay times and filament modes for the Micro-Ion

gauge.

Using RS-485 communications, you can use the IDT and SF commands to

change the behavior of the Micro-Ion gauge. See page 51.

Gauge Button

Gauge LED

Table 3-2 Defaults for Micro-Ion Gauge Filament Material

Function Default for Tungsten Filaments Default for Yttria-coated Iridium Filaments

Micro-Ion gauge delay time Module software determines the

appropriate amount of time to wait

before the Micro-Ion gauge turns

ON with decreasing pressure

Micro-Ion gauge turns ON, without delay, as

soon as operational pressure is achieved with

decreasing pressure.

Micro-Ion gauge filament mode Manual (see Table 3-17). Alternating (see Table 3-17).

MKS 356 Micro-Ion Plus Series User Manual

Questions and Answers: