INFICON XTM/2 Thin Film Deposition Monitor - Manual (Page 54)

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XTM/2 Operating Manual
3.2.1 Verifying / Establishing Earth Ground
If local facilities engineering cannot provide a low impedance earth ground
close to the instrument, the following procedure is recommended.
Where soil conditions allow, drive two ten foot copper clad steel rods into the
ground six feet apart. Pour a copper sulfate or other salt solution around the
rods to improve the soil’s conduction. A near zero resistance measurement
between the two rods indicates that a desirable earth ground has been
established. In severe cases it may take several soakings of solution over
several days to reach this condition.
NOTE: Keep connections to this grounding network as short as possible. Most
noise transients contain significant power at high frequencies. A long
path adds to the ground circuit's inductance and thereby increases its
impedance at these frequencies.
3.2.2 Connections to Earth Ground
The ground connection on the instrument is a threaded stud with a hex nut. It
is convenient to connect a ring terminal to the ground strap, thus allowing a
good connection with easy removal and installation. See
Figure 3-1 for the
suggested grounding scheme. In many cases, a braided ground strap is
sufficient. However, there are cases when a solid copper strap (0.030" (0.762
mm) thick X 1" (25.4 mm) wide) is more suitable because of its lower RF
impedance.
Figure 3-1 System Grounding Diagram
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*URXQG
6WXG
(DUWK
*URXQG
7UDQVGXFHU
)HHGWKURXJK
9DFXXP 6\VWHP