LQ500
10
■
Wiring Precautions
(1) Provide a switch and a fuse to isolate the unit from
the mains power for ease of maintenance.
(2) Ground the LQ500 with 100 ohm or less ground
resistance. Do not use a common ground shared by
other power equipment.
(3) Use the provided system cables for communication
and power supply between detector and converter.
Connect cables to the terminals that match the
marking on the cables.
(4) Use a sheathed cable with 2mm
2
cross-sectional
area for AC power cable.
(5) The cables should be free from vibration and should
have no slack in the cables.
(6) Wire the LQ500 output in conduit separated from
those of AC power cable, control signals, alarm
signal or other cables which could become the
source of noise.
(7) Use a 2-wire shielded sheathed cable to wire the
LQ500 output (4-20mAdc) and conductivity signal.
Ground the shielded cable on the receiving
instrument side for both cable.
(8) As the cable port is made air-tight using a packing,
tighten the cable gland securely when all the wiring
is completed. If the diameter of the cable is smaller
than the inside diameter of the packing, enlarge the
cable diameter to the same size as the packing by
wrapping valves around the cable Its suitable
diameter is 11mm.
Tighten the terminal screws securely. Its suitable
torque is 1.0 to 1.7 N
⋅
m.
(9) Screws at the terminals are needed to tighten with
1.2 N·m torque (1.4 N·m is maximum).
(10) Do not turn on the power supply under the
uninstalled condition.
(11) Each cable in the communication cable and power
supply cable between detector and converter has
banded marks for each terminal. Connect them
correctly without any mismatches.
L1
L2
Tx+
TX-
Rx+
Rx-
SG
FG
+24V
0V
FG
Ec+
Ec-
FG
Tx+
Tx-
Rx+
Rx-
SG
FG
+24V
0V
FG
Communication cable
Power supply cable
Converter
Power supply 100 to 240 Vac, 50/60Hz
Ground terminal (PE)
(Ground resistance 100 ohm or less)
Density (consistency) measurement output
(4-20mAdc, 750 ohm max., isolated output)
Density multiplier switching voltage inputs
(H level: 20 to 30 Vdc, L level: 2 Vdc or less and Input
resistance: Approx. 3k ohm)
Density meter error or maintenance-in-progress
contact output (Contact capacity: 125Vac,0.1A)
External synch. Control contact signal input
(The load of contact: About 5Vdc, 0.1A)
Chassis ground terminal
(Ground resistance 100 ohm or less)
RF part
Conductivity
signal input
(4-20mAdc)
CVVS
CVVS
CVVS
Ground terminal
(Ground resistance 100 ohm or less)
AO+
AO-
DI3
DI2
COM2
DO1
COM1
DI
COM
FG
CVVS
CVV
CVV
Figure 8. External connections
Notice 1: Do not connect to the “FG” terminals neither communication cable nor power supply cable in the
detector side.
Notice 2: Either “PE” terminal on the terminal block in the converter on the chassis ground terminal of the
unit should be grounded with 100 ohm or less ground.
Notice 3: Ground the shielded cable on the receiving instrument side.
