2
Operating principle
■
■
Normally the internal sensor is attached to a permanent
magnet, as shown below. If an earthquake occurs and the
sensor is subjected to a force that exceeds the selected
horizontal acceleration, the sensor instantly drops and
presses a lever, which activates a micro switch.
Micro switch
Micro switch
NC
NO
COM
NC
NO
COM
Permanent magnet
Lever
Lever
Sensor
Permanent magnet
Sensor
Handling Precautions
If the locking screw is fastened, the sensor is
pushed up and is unable to drop. The locking
screw must be removed before use.
2. Part names
S
E
R
ET
E
T
S T
NC
NO COM
0
20
10
VBC7000
Scale plate
Ground terminal
Cover
Level adjustment screws
Grommet with
membrane
Indication window
Spare screw
Locking screw
Level
adjustment nut
Setting knob
Base
Mounting holes
Side panel
Level
Terminals
Ball chain
3. Installation and wiring
CAUTION
To prevent electric shock, connect the wiring for the
•
power last.
Check the wiring before turning the power on.
•
Otherwise electric shock or damage to the device may
occur.
Mount the device on a firm wall or pillar. Otherwise a
•
malfunction may occur.
Mount the device vertically, using the level, to prevent
•
malfunction.
Never remove the cover. Doing so might cause a
•
malfunction.
Installation
■
■
Hold a plumb line against the wall or pillar where the
1.
detector is to be mounted and determine the position of
the mounting holes using this line as a datum.
Attach the detector firmly using four M6 screws in the
2.
four mounting holes.
After loosening the two level adjustment screws and the
3.
level adjustment nut, move the base back and forth and
around so that the ball chain is not in contact with the
perimeter of the level hole, and then fasten the screws
and nut temporarily. Adjust the base carefully so that the
ball chain is positioned in the center of the level hole,
and tighten the screws and nut securely.
Handling Precautions
If the ball chain is touching the perimeter of the
level hole, faulty operation may occur.
Adjust the scale plate so that the “0” is in line with the
4.
pointer on the base, and fasten securely.
10
20
0
Ball chain
Center
Wiring
■
■
CAUTION
Do the wiring work in conformity with the electric
•
facility technical standards.
The grommet membrane protects against dust. Cut it
•
only where necessary for the wires to pass through.
Do not put wire around the setting knob.
•
Connect the ground terminal to the earth. Otherwise if
•
there is an insulation failure or the like, there will be an
electric shock hazard.
Normal position
Terminals
NC NO COM
Loosen the side panel retaining screw and remove the
1.
side panel.
Pass insulated wires through the grommet membrane.
2.
Connect the wires to the terminals.
3.
After wiring, re-attach the side panel.
4.
After installation and wiring, remove the locking screw
5.
and replace it with the spare screw to protect against
dust. Keep the locking screw in case there is a need to
move the detector in the future.
