CLC Series - First Sensor

CLC Series
Miniature capacitive continuous liquid level sensors
FEATURES
· Contact-free measurement of
continuous liquid level
· Measurement of both metallic and
non-metallic substances
· Measurement of granular or
pulverised materials
· Positioning/proximity sensor
· Displacement sensor
· Easy mounting
· RoHS compliant
· Quality Management System according
to ISO 13485:2003 and ISO 9001:2008
SPECIFICATIONS
ELECTRICAL CONNECTION
Maximum ratings
Supply voltage (VS)
Output voltage (Ri=1 kΩ)
Operating temperature range
5.5...15 VDC
5V
-20 ... 85 °C
VS
Analog
1-Wire
Teach-in
GND
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CLC Series
Miniature capacitive continuous liquid level sensors
PERFORMANCE CHARACTERISTICS
The sensor’s performance strongly depends on surrounding conditions, i.e. air gap, media to be
measured, container material and ground reference.
Characteristic
Min.
Measuring range (vertical)
Typ.
Max.
Unit
100
mm
0
1
Resolution
6
Response time
10
bi t
50
1000
ms
Note:
1. At 3 mm distance between sensor and medium.
OUTPUT SIGNAL
The sensor calculates an actual measurement value between the Teach-In points ‘LOW’ and ‘HIGH’. LOW
corresponds to 0 % and HIGH equals 100 %.
Output
0%
25 %
50 %
100 %
RS232
0x01
0x3F
0x80
0xFE
Analog
0.5 V
1.5 V
2.5 V
4.5 V
ELECTRICAL CHARACTERISTICS
Pin
Pin name
1
V S4
Explanation
Supply pin2
Min.
Typ.
Max.
Unit
5.5
9
15
V
8.5
10
mA
V
Current draw of sensor
7
2
Analog
5
Analog output (Ri=1 kΩ)
0.5
4.5
3
5
RS232 Out, 9600, 8N1
0
5
-0.25
5.25
1-wire
Output voltage (Ri=1 kΩ)
4
TI
3
Teach-in
Current draw
5
GND
1
V
mA
Ground
Note:
2. Length of power supply cable must not exceed 2.5 m.
3. Only for Teach-In, do not connect during operation. (TIHIGH=4.5...5.25 V, TILOW=-0.25...0.5 V)
4. The quality of the supply voltage (with regards to ripple or other disturbances) may have an impact on the accuracy of the
measurement.
5. No protection against electrical surge (e.g. with inductive load)
ELECTRICAL CONNECTION (cont.)
Pin 1
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CLC Series
Miniature capacitive continuous liquid level sensors
DIGITAL OUTPUT
The Sensor has a TTL RS232 output (only TxD) with 9600 Baud, 8N1.
It can be visualised on a PC, using a TTL RS232 adapter and a terminal programme (i.e. Hyper Terminal).
The protocol always starts with a start byte ‘0x00’ followed by a data byte with the current level value in the
range of ‘0x01' = 0% to '0xFE’ = 100%. This range is linearly distributed between the ‘LOW’ and ‘HIGH’ TeachIn points. The data byte must not contain a ’0x00’ to clearly distinguish it from the start byte!
Example:
Byte
Mode
Output (Hex)
1
Start
0x00
2
Data
0x89
3
Start
0x00
4
Data
0x90
5
Start
0x00
6
Data
0x89
...
...
...
n
Start
0x00
n+1
Data
0x89
MECHANICAL CHARACTERISTICS
Wall thickness (glass) without air gap
max. 5 mm
Wall thickness (unfoamed plastic) without air gap
max. 5 mm
Connection output
5 pin JST connector
(VS, Analog out, 1-wire digital out, Teach-in and GND)
Mechanical fixation
Double-sided adhesive tape
MOUNTING
· The optimal distance between sensor and medium is <2 mm.
· The maximum distance between sensor and medium is 5 mm of which 80 % must be of plastic or glass
(less than 20 % air gap).
· The sensor must be fixed on a surface free of grease or bubbles.
CLC
sensor
Teachable
measurement
range
Note:
Please be aware that the sensor needs to be
taught in the application with its specific
mounting and environmental conditions. Any
change in those conditions may result in
erroneous measurements. Environmental
conditions are defined by the presence,
absence or position of objects in the vicinity
of the sensor and/ or changes of electrical
potentials.
Container wall
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CLC Series
Miniature capacitive continuous liquid level sensors
GROUND REFERENCE
The CLC sensor needs a proper ground reference (GND) to achieve optimum results.
Toroidal transformer
If a toroidal transformer is used as a power supply, the capacitive coupling between primary and secondary coil
is sufficient to ensure proper grounding.
Switched power supply
In case a switched power supply is used (which is usually floating), the ground reference could be oscillating by
as much as 50 % of the mains voltage, potentially resulting in erroneous measurements.
Solutions:
Non-floating ground reference
To ensure non-floating of the ground reference, the sensor's GND pin has to be connected to earth potential
(PE). However, this setup could result in a leakage current causing the residual current circuit breaker to
switch. Further, a galvanic connection does exist between the sensor and PE.
Power
supply
+
+Vs
-
GND
CLC
PE
Virtual ground reference
A capacitor between the sensor's GND pin and earth potential (PE) will solve the problem of leakage current
and should be used in most cases. In this setup a galvanic isolation is established between the sensor and PE.
Power
supply
+
+Vs
-
GND
CLC
0.1 µF
PE
Note:
Best results are achieved with a metal plate underneath the container which is connected to the
sensor’s GND.
Wherever possible, ensure that the sensor’s PCB base plate is mounted such that it comes closest
to the media to be measured and adheres to the container.
For guidance regarding both technical and application-specific aspects please contact First Sensor.
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CLC Series
Miniature capacitive continuous liquid level sensors
TEACH-IN
The Teach-In (TI) mode allows for a permanent storage (EEPROM) of both low and high level values of the
measurement range. This range is determined by the sensor pad. The TILOW mode stores the value for the
empty or low level container and adapts to the corresponding application conditions. The TIHIGH mode stores the
value of the container filled to the desired max. level. By factory default the sensor is ‘formatted’ and needs to
be taught to provide an output signal.
Preconditions for successful Teach-In
·
·
·
·
·
·
Do not touch the sensor or container during the Teach-In or measuring process.
The sensor must be in original mounting position.
After connecting to VS the sensor must level off for 2 sec.
Important: The sensor must first be taught LOW to adapt to the ambient conditions, then HIGH.
The TIHIGH value must not be lower than the TILOW value.
Best results will be achieved when GND is connected to earth potential (see GROUND REFERENCE).
Note:
The maximum tolerable voltage range for the TI pin is -0.25…+5.25 V.
TILOW mode:
Apply voltage between 0 and 0.5 V for at least 500 ms at the Teach-In pin.
After 1 sec. the value is stored in the EEPROM.
TIHIGH mode:
Apply voltage between 4.5 and 5 V for at least 500 ms at the Teach-In pin.
After 1 sec. the value is stored in the EEPROM.
Under normal conditions, the TI-Pin delivers 2.5 V.
It is possible to re-teach the HIGH level only (in case, the LOW level remains the same). A re-teaching is only
possible after having disconnected the supply voltage. However, if the LOW level needs to be changed, the
sensor first has to be formatted (see Reset).
Reset
The sensor can be reset to factory default (’format’) as follows:
1. Disconnect the sensor from VS .
2. Connect the TI-Pin (pin 4) to GND.
3. Connect the sensor to VS for at least 2 sec.
4. Disconnect the sensor from VS and formatting is completed.
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CLC Series
Miniature capacitive continuous liquid level sensors
OUTLINE DRAWING
102 ±0.3
24.5 ±0.3
1
100
Sensor pad
102 ±0.3
24.5 ±0.3
5.0 ±0.1
25 ±0.2
Note:
The max. sensor height incl. connector is 8 mm.
Label
Connector
dimensions in mm
ORDERING INFORMATION
Series
Options
C LC
Measuring range
100
100 mm
Output
S*
Supply
RS232 and
0.5...4.5 V
15
5.5...15 V
Housing
N
No housing
* Ri=1 kΩ
Example:
C LC
100
S
15
N
Accessory
(Not included in delivery! Please order separately.)
Order No.
Description
ZK000133
JST connector/cable assembly (approx. 29 cm cable length)
First Sensor reserves the right to make changes to any products herein.
First Sensor does not assume any liability arising out of the application
or use of any product or circuit described herein, neither does it convey
any license under its patent rights nor the rights of others.
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