INFICON Composer Gas Concentration Controller - Manual (Page 32)

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Composer Operating Manual
1.10.2.5 Protective Grounding Requirements
The Controller and Transducer must be connected to a low impedance and
reliable earth ground using a high quality solid copper conductor of the shortest
possible length. It is recommended that this wire be a minimum of 16 gauge and
that any connector terminals be soldered. Although the Transducer will
normally be grounded by the Reactor’s Delivery Line tubing, an additional
ground connection to one of the 1/4"-20 mounting holes must be used for
optimum results.
CAUTION
Verify that the Reactor is grounded and that the metal
Delivery Line tubing makes a low impedance
connection to this ground.
1.10.3 Electrical Grounding and Shielding
Requirements
Careful consideration of simple electrical guidelines during installation will
avoid many problems caused by electrical noise.
To maintain the required shielding and internal grounding as well as insuring
safe and proper operation, the instrument must be operated with all enclosure
covers and option panels in place. These must be fully secured with the screws
and fasteners provided.
1.10.3.1 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 6 feet (2 meters) 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 is
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.