Ultramodern welding techniques and advances in the miniaturization of electronic circuits now make it possible to manufacture a pre-insulated, piezoresistive micro-transmitter with properties that were no more than a dream 10 years ago. The circuit is based on the PromComp principle which KELLER offered in a separate version as a laboratory device 20 years ago when it attained accuracy of 0,1 %FS over a temperature range of 100 K. In those days the electronic circuitry was the size of a cigar box, but now it can be accommodated on a print that is a mere 12 mm in diameter. Although this digital component is only slightly more expensive to produce than an analog circuit, it allows a piezoresistive sensor to be calibrated to an accuracy of 0,5 %FS over a potential temperature range of 100 K. A temperature sensor divides the temperature range into fields with a width of 1,5 K each. Two values are assigned to each field in an EEPROM: one value for the zero point and another for the amplification, determined by mathematical interpolation in the calibration process. During operation, the corresponding values are ‚switched in’ at the relevant temperatures. The electronics make it possible to assign up to 120 fields so that a temperature range of 180 K can be covered. The 100 K restriction for series 21 PY is due to the sensor This means that more or less any temperature can be the ‚calibration temperature’ for these transmitters. Calibration and temperature errors within a temperature field are within ± 0,2 %FS. The remainder of the error bandwidth of ± 0,5 %FS can be attributed to linearity and stability errors. So it’s goodbye to the days when sensor engineers had to struggle every day with TKN (zero point) and TKG (gain/amplification) problems. The 21 PY product line is outstanding due to its extreme ruggedness towards electromagnetic fields. The limits of the CE standard are undercut by a factor of up to 10 with conducted and radiated fields, thus making this product ideal for use in harsh industrial environments.
The Y-line transmitters have an extremely small temperature error. This is achieved using an additional circuit containing a temperature sensor that subdivides the temperature range into fields that are 1,5 Kelvin (K) wide. The TK zero and TK compensation values are calculated for each field and programmed into the additional circuit. During operation, these values are fed into the analogue signal path depending on the temperature. Each temperature is the "calibration temperature" for this transmitter. The Series 23 (S)Y/25 Y product line is outstanding due to its extreme ruggedness towards electromagnetic fields. The limits of the CE standard are undercut by a factor of up to 10 with conducted and radiated fields.
The Kobold Differential Pressure Transmitter model PAD is a micro processor-based high performance transmitter, which has flexible pressure calibration and output, automatic compensation of ambient temperature and process variable, configuration of various parameters, communication with HART ® protocol. The application is very various, as measuring pressure, flow and level by application method. All data of sensor is to be input, modified and stored in EEPROM. As an option the Kobold Pressure Transmitter is also available as a flow meter. This flowmeter model PAD-F has added the totalizing function in the PAD transmitter. So it is available to check the flow rate and totalizing flow. It measures the flow rate by using differential pressure without compensation of temperature and static pressure. The shape of the PAD-F is the same as the standard device and it is only the terminal block which is different since there are two more terminals for the read-out of the pulse output.
The KOBOLD Pressure Transmitter model PAS is a micro processor-based high performance transmitter, which has a flexible pressure calibration and a flexible output signal. It has an automatic compensation of ambient temperature and process variables. A communication with the instrument and a configuration of various parameters is possible via the HART ® protocol. All data of sensor is to be input, modified and stored in an EEPROM.
LEO Record is an autonomous battery powered instrument with digital display designed to record pressure and temperature over long periods. The pressure is measured and displayed once per second (shortest interval). The top display indicates the actual pressure, the bottom display shows the record status. All LEO Record versions have two operating keys. The left key is to turn the instrument on, to select the functions and the pressure units. The right key executes the selected function or unit.:
The high-pressure transducers of the 10LHP series have robust housing of stainless steel, giving them optimum long-term stability for a range of OEM applications. The metal diaphragm is welded on front-flush and gap-free, separating off the piezoresistive pressure sensor made of silicon from the measuring medium. Every pressure transducer is measured over the entire pressure and temperature profile and is supplied with a detailed calibration sheet.
Technology
• Insulated piezoresistive pressure sensor encapsulated in an oil-filled metal housing • Ideal for mounting with O-ring and support ring • Typical output signal range of 160 mV/mA
Typical applications
• OEM • Industry • Laboratory • Oil and gas • Oceanology
The compact pressure transmitters of the 21Zio series can be used both as a pressure measuring instrument and as a pressure switch. Thanks to the universal IO-Link interface according to IEC 61131-9, the sensor is flexible and easily and quickly integrable into intelligent automation and other systems. The switching functions and other parameters can be called up and configured directly via IO-Link. In this way, machine downtimes are reduced to a minimum and personnel are relieved.
LEO 2 is a compact, micro-processor (µP) controlled, highly accurate and versatile pressure measuring instrument with digital indication. The piezoresistive pressure transducer as the heart of the instrument has gone through extensive pressure- and temperature tests. Its characteristics are stored in the instruments internal EEPROM. The µP of the LEO 2 reads the characteristic values and calculates therefrom the pressure to an accuracy of < 0,1 %FS at room temperature. The pressure is measured twice per second and displayed. The top display indicates the actual pressure, the bottom display shows the Max.- or Min.- pressure since the last RESET. Also available as intrinsically safe version (LEO 2 Ei).
The LEO 5 combines the notable features of Keller’s successful LEO-Record and LEX 1 digital pressure gauges, featuring an IP66-rated stainless steel enclosure. This robust housing combines contemporary microcontroller-based electronics and capacitive-touch controls, operated through the environmentally-sealed safety glass front panel. The large backlit LCD display ensures readability in any lighting conditions. Two selectable measurement modes, standard and peak, are included to ensure maximum versatility. In standard mode, high-resolution pressure measurements are taken twice per second. When operating in peak mode, sampling frequency increases to 5 kHz with 16 bit resolution. The LEO 5 interfaces with a PC via USB connectivity, allowing access to active measurements and recorded data including pressure, peak pressure, temperature, and measurement interval. PC connection also allows device configuration, firmware updates, and recharging of the integral accumulator power supply. The unique modular design of the LEO 5 makes possible adaptation to customer-specific measuring requirements.
LEO 5 CA offers a user-friendly way to represent the pressure measurement at the bottom of a tank as the quantity of remaining liquid. At the push of a button, the microcontroller performs the calculations using the information of the tank shape and dimensions and displays the remaining tank content quantity on the clearly legible 5-digit LED display in the desired unit (litres, gallons etc.). The unit is configured using a PC and the easy-to-use software so that the filling level, which determines the pressure, can be converted into an appropriate filling quantity. First the tank shape is selected, then the tank dimensions and the specific gravity of the liquid are entered. It contains the most current tank shapes. The program covers the most common tank shapes, but also enables any shape by entering the parameters into a specified table. The exclusive use of absolute pressure sensors in the LEO 5 CA system eliminates the use of capillary vented cables with all the problems associated with a gauge pressure measurement. The LEO 5 CA housing integrates an air pressure sensor, ranged between 0,8 bar and 1,2 bar absolute. The sensors to measure the hydrostatic pressure at the bottom of the tank are calibrated from 0,8 to 1,8 bar abs for tanks up to 5 m in height, and 0,8 to 2,3 bar abs for tanks up to 10 m in height. The pressure difference, calculated by the micro-controller, is the relative hydrostatic pressure. The content of a pressurised tank is determined using the difference between the measurements from two absolute pressure sensors located at the top and bottom of the tank An accuracy of the system of up to 2 mbar (corresponding to a 2 cm water column) is achieved using a computerised calibration and compensation procedure for the pressure sensors. LEO 5 CA makes it possible to connect various pressure probe transmitter versions (with thread, front-flush with flange, or submersible sensors). The power supply to the system (8 to 28 V) can be provided externally or internally from an accumulator or a battery. The display is obtained by pressing the button on the front, and the value appears for a configurable duration. The LEO 5 CA has two switch outputs with configurable functionality and threshold values. The device must be supplied externally if the switch outputs are used.
Proven primary pressure standard Deadweight Tester / Pressure Balances are the most accurate instrument available on the market for the calibration of electronic or mechanical pressure measuring instruments. The direct measurement of the pressure (p = F / A), as well as the use of high-quality materials enable a very small measurement uncertainty, in conjunction with an excellent long-term stability of 5 years (recommended in accordance with German Calibration Service DAkkS). The deadweight tester / pressure balance has therefore been used for years in factory and calibration laboratories in national institutes, research laboratories and in industry. Stand-alone operation Due to its integrated pressure generation and the pure mechanical measuring principle, the model LR-Cal LDW-P is ideal for on-site use for maintenance and service. Basic principle Pressure is defined as the quotient of force and area. The core component of the model LR-Cal LDW-P is therefore a very pecisely manufatured piston-cylinder-system, which is loaded with masses in order to generate the individual test points. The masses applied are proportional to the target pressure and this is achieved through optimally graduated weights. As standard, these masses are manufactured to the standard gravity (9.80665 m/s²), though the can be manufactured to a specific location (gravity) and also DAkkS-calibrated. Easy operation Depending on the instrument version the pressure is set via an integrated pump or via an external pressure supply by the use of control valves. For fine adjustment a very precisely adjustable spindle pump with a precision spindle running only within the pump body is mounted. As soon as the measuring system reaches equilibrium, there is a balance of forces between the pressure and the mass load applied. The excellent quality of the system ensures that this pressure remains stable over several minutes, so that the pressure value for comparative measurements can be read without any problems, or also so that more complex adjustments can be carried out on the item under test.
The dV-2 Cool was designed for monitoring tasks at refrigerators and refrigerating plants. Vapour pressure/temperature graphs for 5 refrigerants are saved in the unit and can be selected by pressing a button.
At the touch of a button, the battery-driven instrument switches the LCD-display between vapour temperature and pressure indication, with the display offering a choice of bar / °C or PSI / °F.
The high resolution display means that dV-2 Cool can also be used for measuring leaks in vacuums.
The rugged dV-2 Cool with a stainless steel pressure sensor can optionally be fitted with a protective rubber covering. The face of the instrument can be rotated towards the pressure connection, thus allowing the ideal alignment of the display when fixing the instrument.
The dV-2 Cool has the following functions:
GAS : Selection of the refrigerant.
UNITS : Switching between bar / °C and PSI / °F
CONT : The instrument turns off 15 minutes after the last key function. Activating CONT (Continuous) deactivates this automatic turn-off.
BAT LOW : The battery symbol illuminates when battery power is low.
Refrigerant: In the standard version, the vapour pressure/temperature graphs of the following refrigerants are stored: R22, R12, R507, R404a, R134a. Other refrigerants optionally available (on request).
The compact ECO2 digital manometers are budget-friendly and provide a good resolution. The minimum or maximum value since the last reset can be displayed at the same time as the current pressure value in a wide variety of units of pressure. The swivel adapter allows the device to be optimally positioned. Power is supplied by a conventional CR2430 coin cell battery (provided).
The pressure transmitters of the 4LC series use the chip-in-oil developed by KELLER, uniting a pressure measuring cell, digital temperature compensation and signal processing in a compact housing made of stainless steel or Hastelloy. The transmitters are extremely resistant to environmental influences and deliver compensated measurement results as an analog, ratiometric 0,5...4,5V output signal over a wide temperature range.
The pressure transmitters of the 4LD series use the chip-in-oil technology developed by KELLER, uniting a pressure measuring cell, digital temperature compensation and signal processing in a compact housing made of stainless steel or Hastelloy. The transmitters are extremely resistant to environmental influences and delivery highly accurate measurement results as a digital output signal. The I2C interface and the low supply voltages make it easy to integrate in microcontroller-based systems. The extremely low power consumption is ideal for battery-operated devices. The D line is perfect for IoT solutions.
The remote data transmission unit ARC1-Box with logger function is encased in a robust, water-tight aluminium housing. This unit records measurements made by external sensors (e.g. a level sensor) and periodically transmits the collected data via 2G, 3G, 4G or LoRaWAN. The high-performance battery and sophisticated power management enable autonomous operation for up to 10 years. KELLER provides a range of licence-free software solutions for configuration and data processing. The easiest and most convenient way to access the collected data is via Keller PressureSuit Cloud.
The remote data transmission unit ARC1-Box-SB with logger function is equipped with safety barriers and, in combination with intrinsically safe transmitters, it is suitable for use in hazardous applications. The unit is encased in a robust, water-tight aluminium housing. It records measurements made by external sensors (e.g. a level sensor) and periodically transmits the collected data via 2G, 3G, 4G or LoRaWAN. The high-performance battery and sophisticated power management enable autonomous operation for up to 10 years. KELLER provides a range of licence-free software solutions for configuration and data processing. The easiest and most convenient way to access the collected data is via Keller PressureSuit Cloud.
The remote data transmission unit ADT1-Tube is encased in a robust, stainless steel housing, which is ideally suited to installation in 2" monitoring pipes. The LoRa module, which can be configured on a country-specific basis, establishes a connection with the Internet and makes it possible to collect measurement data in a low-cost and energy-saving manner. These autonomous devices can be linked with digital level sensors and pressure transmitters in the KELLER D and X product lines. With three conventional, high-quality AA batteries, the system can operate autonomously for up to 5 years. The LoRaWAN provider can be selected freely or an in-house or open source infrastructure and associated services can be used. The easiest and most convenient way to access the collected data at the end of the transmission chain is via Keller PressureSuit.
The remote data transmission unit ADT1-Box is encased in a robust, water-tight plastic housing. The LoRa module, which can be configured on a country-specific basis, establishes a connection with the Internet and makes it possible to collect measurement data in a low-cost and energy-saving manner. These autonomous devices can be linked with digital level sensors and pressure transmitters in the KELLER D and X product lines. With three conventional, high-quality AA batteries, the system can operate autonomously for up to 5 years. The LoRaWAN provider can be selected freely or an in-house or open source infrastructure and associated services can be used. The easiest and most convenient way to access the collected data at the end of the transmission chain is via Keller PressureSuit.
The remote data transmission unit ARC1-Tube with logger function is encased in a robust, stainless steel housing, which is ideally suited to installation in 2" monitoring pipes. This unit records measurements made by external sensors (e.g. a level sensor) and periodically transmits the collected data via 2G, 3G, 4G, NB-IoT, LTE-M or LoRaWAN. The high-performance battery and sophisticated power management enable autonomous operation for up to 10 years. KELLER provides a range of licence-free software solutions for configuration and data processing. The easiest and most convenient way to access the collected data is via Keller PressureSuit.
The pressure transmitters of the 7LC series use the chip-in-oil developed by KELLER, uniting a pressure measuring cell, digital temperature compensation and signal processing in a compact housing made of stainless steel or Hastelloy. The transmitters are extremely resistant to environmental influences and deliver compensated measurement results as an analog, ratiometric 0,5...4,5V output signal over a wide temperature range.
The pressure transmitters of the 8LC series use the chip-in-oil developed by KELLER, uniting a pressure measuring cell, digital temperature compensation and signal processing in a compact housing made of stainless steel or Hastelloy. The transmitters are extremely resistant to environmental influences and deliver compensated measurement results as an analog, ratiometric 0,5...4,5V output signal over a wide temperature range.
The pressure transmitters of the _LC series use the chip-in-oil developed by KELLER, uniting a pressure measuring cell, digital temperature compensation and signal processing in a compact housing made of stainless steel or Hastelloy. The transmitters are extremely resistant to environmental influences and deliver compensated measurement results as an analog, ratiometric 0,5...4,5V output signal over a wide temperature range.
The 9FLC series is a special version of the 9LC pressure transmitter. The flanged housing can be mounted using an O-ring or welded on. As with all C-line products, the chip-in-oil technology developed by KELLER is used here, uniting a pressure measuring cell, digital temperature compensation and signal processing in a compact housing made of stainless steel or Hastelloy. The transmitters are extremely resistant to environmental influences and deliver highly accurate measurement results as an analog, ratiometric 0,5...4,5V output signal over a temperature range of -40 °C to 150 °C.