Wiring - Toshiba LQ500 Operation Manual

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3.5 Wiring

Figure 3.5.1 on the next page shows connections to the density meter and the external units. Figure
3.5.2 shows wiring assignment to a converter terminal. Refer to these figures for correct wiring.
[IMPORTANT]
(1) A density meter has to be separated from the power supply line when performing the
maintenance and inspection operation. A fuse must be installed on the power supply side to
protect a switch and the power. A power requirement for this unit is approximately 50 VA.
Power consumption of this meter is 24VA (at 100VAC).
(2) Grounding resistance should be 100 Ω or less and the grounding should be made independently
from the one used for power equipment.
(3) To connect between the detector and the converter, use the attached power cable (to supply
DC power supply) and communication cable. Connect these cables by matching the terminal
symbols of the detector RF section's terminal block (can be seen when the RF section cover
is removed) and the converter's terminal block with those shown on each cable.
(4) Use power cables of 2 mm
maximum. In addition, use an M4 size crimped terminal for each terminal connections.
(5) Consider wiring when installed so that vibration or sway will not be applied to cables.
(6) Output signal wires should be installed in thick walled steel conduit and separated from AC
power supply, control signal, alarm signal and other wires that may become a source of noise.
(7) Signal wires of the density meter measured value (4-20 mA output) should be a 2-conductor
shielded cable (CVVS 2 mm
instrument side. When conductivity correction is employed, use the same type of 2-conductor
shielded cable (CVVS 2 mm
should be made on the receiving instrument side.
(8) Cable wiring port is airtight with gland and packing; therefore, tighten the cable gland securely
when wiring is completed. Applicable cable sizes are 11 to 13 mm in diameter. If the cable
diameter is smaller than the inside diameter of the gasket, wind tape or something around the
cable until the cable diameter becomes about the size of the inside diameter of the gasket.
(9) Tighten terminal screws securely. Appropriate tightening torque for terminal block screws is
1.2 N•m (1.4 N•m MAX).
(10)Do not apply power when the density meter is not installed properly in the piping system.
Leakage of radio waves may cause interference with other equipment.
2
or more in sectional area and its voltage drop should be 2V
2
) and the grounding of the shield should be made on the receiving
2
) for conductivity signal wires and the grounding of the shield
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