Liquid Leakage Sensor Amplifier
K7L-AT50
5
Nomenclature
■
DIP Switch Settings
Setting Sensing Range
•
Set the sensing range according to the impedance of the liquid to
be detected. (If the sensing range DIP switch pins are set in a way
not shown above, the actual range used will be the largest one by
default.) For the setting method, refer to the label on the side of the
Sensor Amplifier.
•
It is possible to set the resistance value within the set sensing
range using the resistance value adjuster. At time of delivery, it is
set to the largest possible value and this setting can be used for
normal use.
•
The resistance value adjuster is a precision component. Do not
apply a torque to the resistance value adjuster in excess of the
specified one. Doing so may cause the resistance value adjuster to
be damaged.
Applicable torque:
•
Rotational torque: 9.81 m N·m max.
•
Detent strength: 29.4 m N·m min.
Operation
■
Countermeasures Against Noise
Noise Canceller Function for Highly
Sensitive Impedance Detection
The K7L Liquid Leakage Sensor Amplifier detects liquids with imped-
ance as high as 50 M
Ω
and connects to the Sensing Band through a
cable that can be extended up to 50 meters. Countermeasures
against external noise are especially important for the Sensing Band
and connecting cable because they pick up external noise like an
antenna. The K7L incorporates the noise canceller function
described below.
Connected with 3-conductor Cable that
Offsets Inductive Noise (Patent Pending)
A VCT cable with three conductors (lines) is used. Line 1 is con-
nected to the Sensing Band and line 2 is left open. Lines 1 and 2 are
almost in the same position and thus will experience the same noise
level. The K7L obtains the difference between these signals. This
means that the noise signals in lines 1 and 2 are offset against each
other and a reading for the signal, without inductive noise, can be
made.
Output indicator (red)
(Lit when output
is ON.)
Resistance
value adjuster
Power indicator (green)
(Lit when power is sup-
plied.
DIP switch
Range number
Sensing range
Range 0
0 to 250 k
Ω
Range 1
0 to 600 k
Ω
[
Range 2
0 to 5 M
Ω
Range 3
0 to 50 M
Ω
DIP switch
Output mode
Output OFF when liquid leakage
detected.
Output ON when liquid leakage
detected.
Sensing Band
Signal transmission
line
Line 1
Line 2
Connecting cable
K7L signal transmission circuit
Subtraction circuit
Resistance measurement circuit