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 E / 11663 / J 1/6 www.first-sensor.com www.sensortechnics.com 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 E / 11663 / J 2/6 www.first-sensor.com www.sensortechnics.com 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 E / 11663 / J 3/6 www.first-sensor.com www.sensortechnics.com 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. E / 11663 / J 4/6 www.first-sensor.com www.sensortechnics.com 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. E / 11663 / J 5/6 www.first-sensor.com www.sensortechnics.com 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. E / 11663 / J 6/6 www.first-sensor.com www.sensortechnics.com