Wiring - Toshiba LF150 Instruction Manual

4.2 Wiring

IMPORTANT
The grounding terminal of the LF150 detector must be grounded with less than 100
ohm ground resistance. A grounding wire should be as short as possible. Avoid a
common ground used with other equipment where earth current may flow. An
independent ground is preferable.
The flowmeter accuracy may be affected by the way wiring is conducted. Proceed with
wiring with following precautions:
Select the cable runs away from electrical equipment (motors, transformers, radio
transmitters or electrolyte cells) which causes electromagnetic or electrostatic interference.
Deterioration of the circuit insulation occurs if the converter interior or cable ends get
wet or humidified. It causes malfunction to the flowmeter or a problem of noise occurs.
Avoid a rainy day if the flowmeter is to be installed outdoors. Even if indoors, avoid
water from sprinkling over the device and try to finish the wiring as quickly as possible.
As the signal and exciting cables carry low-level signals, run these cables in thick walled
steel conduit separated from other large current wiring. Also do not run these cables in
parallel with other large current wiring.
For the detector whose cables are already wired at the time of shipment, the terminal
housing is closed securely to keep it airtight. Therefore, do not remove the terminal housing
cover or cables. If it is necessary to replace cables for repair work etc., see Sections 4.2.1
and 4.2.2
IMPORTANT
When you replace cables, use new packings for the housing cover and cable
connection.
Contact your nearest Toshiba representative to purchase these packings.
4.2.1 Cables
Use cables shown in Table 4.3 to wire the detector.
Name
Signal cable
Exciting
cable
Note: Nominal cross-sectional area and overall diameter for exciting cable are
dependent on the cable length. Refer to the type specification code table 8.4.
Table 4.3 Cables
Cable type
2-wire shielded chloroprene
sheathed cable
( Rubber covered cable )
3-wire chloroprene
sheathed cable
( Rubber covered cable )
—
Nominal
cross-sectional
area
0.75 mm²
1.25 mm² or
2 mm² (Note)
17
—
６Ｆ８Ａ０９１６
Overall
diameter
12 mm
12 mm or
13 mm (Note)