(max. 4 mm glass or plastic)
Water
Metal
Ceramic
Ceramic
Wall
Plastic granulate
Adjustment
2
Balluff GmbH Schurwaldstraße 9 73765 Neuhausen a.d.F. / Germany Phone +49 7158 173-0 Fax +49 7158 5010 www.balluff.de [email protected]
Presence Detection of Solid Objects
Point-Level Detection through Container Walls
Flush (shielded) Sensors
These capacitive sensors use a larger spherical electrical
which is especially suited as level detectors
Non-Flush (unshielded) Sensors
for liquids, granulates or powders.
Direct Point-Level detection
Flush mountable sensors are normally being used for presence detection of objects or for indirect point
level detection of solids, powders or liquids. The following two setup routines help to assure proper setup
and operations. All BCS sensors allow sensitivity adjustment potentiometer.
The following procedures are outlined for setting a normally open
capacitive sensor for ideal sensing conditions:
1. Mount the sensor in the actual sensing position
2. Set up the target for the worst case condition. This means for a
presence detection application to move the object to the
farthest occurring position from the sensor.
3. All BCS capacitive sensors are already factory preset to their
maximum operational sensing range. The sensor has to move
closer to the target object, if the farthest object position does
not assure a reliable switching. Alternatively, a larger sensor with
a larger sensing range can be chosen.
4. The sensitivity can now be reduced by turning the potentiometer
CCW until the sensor switches off. Increase now the sensitivity
CW by 1/2 turn to set the sensor to its optimal sensitivity setting.
Example:
In the following example, a shielded capacitive sensor in a M12
tubular housing will be used to detect a ceramic plate.
The sensor is factory preset to a maximum rated switching distance
sn of 4 mm to metal or by approximation to your hand. When
moving the sensor towards the target object, the rated switching
distance sn to the ceramic plate has been reduced to approx. 2mm.
This distance is now the maximum permissible switching distance
for the ceramic plate.
To ensure that Balluff’s BCS capacitive sensors work reliably within
their technical specifications, they have a greater sensing distance
than the indicated maximum rated switching distance sn in the
datasheet. If the user decides to adjust the sensor to a switching
distance greater than 2mm for the above described ceramic plate,
the sensor will operate in an unreliable mode. This entails a risk that
temperature and other environmental factors or electrical interferences
may lead to unreliable switching conditions.
Note:
1. Mount the sensor in the actual level sensing position flush to
the non-metallic container wall.
2. All BCS capacitive sensors are already factory preset to their
maximum operational sensing range. The sensor will initially
trigger on the container wall material.
3. The sensitivity has to be reduced by turning the
potentiometer CCW until the sensor switches off. Increase now
the sensitivity CW by 1/2 turn to set the sensor to its optimal
sensitivity setting.
4. The sensor should switch on at 40% to 50% sensing area
coverage - readjust the sensitivity CCW if the coverage is
above 50% and CW if it is below 40%.
1. Mount the sensor in the actual level sensing position flush to the
non-metallic container wall.
2. All BCS capacitive sensors are already factory preset to their
maximum operational sensing range. The sensor will initially
switch on to the container wall.
3. The sensitivity has to be reduced by turning the
potentiometer CCW until the sensor switches off. Increase
now the sensitivity CW by 1/2 turn to set the sensor to its
optimal sensitivity setting.
4. The sensor should switch on at 40% - 50% sensing area
coverage - readjust the sensitivity CCW if the coverage is
above 50% and CW if it is below 40%.
The partition wall may only be made of glass or plastic. A rule of
thumb for the maximum thickness of the wall yields a value of approx.
10 to 20% of the sensor‘s rated switching distance, but max. 4
mm. SMARTLevel sensors can sense through up to 12mm of wall,
but are limited to water-based or conductive liquids.
For very small amounts of liquids and small tank radiuses which do
not allow a tight form-fitting mounting, the sensors should be adjusted
for approx. 30% sensing area.
Note:
Wall thickness
Important:
Different material
properties and conditions have
to be taken into consideration
during the calibration process.
All Balluff BCS capacitive
sensors are therefore equipped
with highly accurate trim
potentiometers to adjust the
device‘s sensitivity. Turning the
potentiometer clockwise (CW)
increases the sensitivity, whereas
counter-clockwise (CCW) turning
reduces it.
Full Setup (normally open)
1. Mount the sensor in the actual level sensing position with
regards to the minimum clearance guide line in our mounting
reference.
2. All BCS capacitive sensors are already factory preset to their
maximum operational sensing range. The sensor will initially
switch on contact with the target material.
3. The sensitivity has to be reduced by turning the
potentiometer CCW until the sensor switches off. Now increase
the sensitivity CW by 1/2 turn to set the sensor to its
optimal sensitivity setting.
This setup procedure assures that the influence of temperature and
material build-up has been reduced to a minimum. In some
instances,the target material creates extensive material build-up or
has a very high relative dielectric constant (conductivity) leading to
uncontrollable repetitive false triggering.
Manual - Capacitive Sensor BCS
Full Setup (normally open)
Empty Setup (normally open)
field
