YOKOGAWA AXG1A Installation Manual page 45

(4) Grounding
WARNING
For the wiring of protective grounding, terminate the
cable finish with round shaped crimp terminal with
insulation cover (for M4 screw), and connect it to the
proctective grounding terminal reliably.
CAUTION
• The grounding should satisfy Class D requirements
(grounding resistance, 100 Ω or less).
• For explosion protection type, the grounding must
satisfy the domestic electrical requirements as
regulated in each country.
IMPORTANT
Improper grounding may result in an adverse effect
on the flow measurement. Ensure that the product is
properly grounded.
The electromotive force of the magnetic flowmeter is
minute and it is easy to be affected by noise. Therefore,
be sure to ground according to Figure 4.5.6. The reliable
grounding equalize the reference electric potentials
(terminal potential) of the sensor and the transmitter, the
measuring fluid potential and the ground potential, and
then reduce the affection by noise.
The grounding rings make a connection between the
measured fluid and the ground and protects the flared
face of lining.
Grounding rings are supplied with the products when
specified with dedicated optional code.
600 V vinyl-insulated cable
Cable cross section area:
2 mm 2 or larger
• Grounding Resistance:
100 Ω or less (Class D requirements)
Figure 4.5.6 Grounding (Remote Sensor)
(5) Installing the Cover
Grounding ring
F0446.ai
<4. Wiring>
CAUTION
• The grounding should satisfy grounding resistance
requirement, 100 Ω or less (Class D grounding).
• For explosion protection type, the grounding must
satisfy the domestic electrical requirements as
regulated in each country.
In case grounding rings are not used.
In case grounding rings
(Available only for metal piping)
are used.
Install the cover to the terminal box by turning it
clockwise. Tighten the cover locking screw (1) (See
Figure 4.5.1) counterclockwise using a hexagonal
wrench (nominal size 3) to lock the cover.
WARNING
• When opening and closing the cover, be sure to
handle the cover carefully so that there are no damage
and foreign matter adhesion at its threads and O-ring.
Keep checking their condition and clean the threads in
case of adhering the foreign matter.
• Replace the cover in case the treads receive
damages.
• Replace the O-ring if there is any scarring or
transformation. And apply silicone based grease at
the O-ring in case of the shortage and exhaustion of
grease.
IMPORTANT
• When closing the cover, close it with both hands until
the cover does not turn in order to bring the housing
and cover into tight contact.
• Tighten while confirming that the cover rotates
smoothly.
44
F0447.ai
IM 01E24A01-01EN