The Series PD-39 X does not measure the differential pressure directly – instead, it uses two absolute pressure sensors to take the measurement indirectly. As well as reducing costs, this differential pressure transmitter is also more robust in relation to unbalanced (one-sided) overloading. The differential pressure range should be at least 5% of the standard pressure range. Each pressure side has two pressure connections, so the Pressure measurements can be displayed and recorded on PC or Laptop with help of the software ControlCenterSeries30 (CCS30) and a seriel interface cable. Export of recordings to usual file formats possible. Up to 128 devices can be connected together into a KELLER Bus-system. The Series PD-39 X does not measure the differential pressure directly - instead, it uses two absolute pressure sensors to take the measurement indirectly. As well as reducing costs, this differential pressure transmitter is also more robust in relation to unbalanced (one-sided) overloading. The differential pressure range should be at least 5% of the standard pressure range. Each pressure side has two pressure connections, so the PD-39 X is easy to use in pressure lines So that the differential pressure can also be measured exactly if the standard pressure range/ differential pressure ratio is high, this series also features the tried-and-tested microprocessorbased technology that is used in Series 30 X. All reproducible pressure sensor errors (i.e. nonlinearities and temperature dependencies) are entirely eliminated thanks to mathematical error compensation. The sensor signals are measured with a 16-bit A/D converter, so the individual standard pressure ranges can be measured to an accuracy of 0,05%FS throughout the entire pressure and temperature range. Digital Interface The transmitters have a bus-compatible two-wire RS485 half-duplex interface which is modelled on the ”MODBUS RTU”. KELLER offers interface converters to RS232 or USB for use here. The READ30/PROG30 program and the protocol are freely available. The interface offers these capabilities: - Readout of pressure and temperature values for both sensors. This allows readout of the diffe- rential pressure as well as the two standard pressure ranges. - Calibration of zero points and amplification. - Scaling of the analog output to different pressure ranges or units. - Configuration settings such as measurement rate, low-pass (LP) filter, bus address, etc. - Readout of information such as serial number, compensated pressure and temperature ranges, etc. Analog Output The analog output is freely scalable via the interface. For flow measurements, the root of the differential pressure can also be outputted. The calculated value can be outputted via an analog interface (0…10 V or 4…20 mA).
The Series 41 X combines the ceramic measurement cell for low pressure ranges with the µP electronics of the digital Series 30 transmitter. The pressure values from the signals of the pressure and temperature sensors are determined by polynomial compensation (see reverse). The values can be displayed and stored on a PC via an RS485 interface and programming can also be carried out. The transmitters are calibrated to the base range. The PROG30 software permits programming of the analog output signal in each section of the range within the base range (e.g. range 100 mbar. Output 4…20 mA for 20…60 mbar). With KELLER RS converters K-100 Series, up to 128 transmitters can be hooked together into a bus system and read by means of a PC or laptop. READ30 software allows the current pressure of each transmitter to be read or the pressure activity of several transmitters to be recorded or stored whilst “on line”.
Piezoresistive pressure transmitter for applications in bio-reactors or autoclaves. The transmitter is compensated up to 150 °C and may be operated continuously or sterilised at this level, including the special circuit electronics The transmitters are supplied in absolute or gauge versions, with current or voltage output. The sensing component is a micro-machined silicon pressure chip of high sensitivity. An independent temperature sensor is integrated on the surface of the silicon chip
Series 22 DT was developed and homologated specially for use in so-called "bivalent" vehicles fitted with engines for combined natural gas/gasoline operation. The unconventional design with a small mass swept by the flow results in a fast response with temperature changes, the temperature being measured by an NTC or PT sensor located directly behind the stainless steel separating diaphragm. The same diaphragm transmits pressure via a capillary to a stress-free mounted silicon measuring cell. The signal processing for pressure and temperature is carried out by an electronic module connected to the sensors by flexible conductors. Mounted to the back of the electronic module, which is directly connected to the 6-pole plug connector are the EMC protection components. A special feature is the immunity from interference from electromagnetic fields up to 200 V/m.
Series 22 offers a reliable cost effective solution for customers requiring medium to high quantities, of mass produced transmitters. Utilising the KELLER automatic brazing lines, this new technology allows crevice-free construction of the pressure port with no internal seals or O-rings, making possible high volumes at low cost. In the brass 22 M, a steel insert and a nickel diaphragm are brazed into a brass housing. In the steel 22 S, all parts are stainless steel (AISI 316 L). The glass feed-through header and silicon pressure sensor are welded to the steel insert underneath the oil filling. The electronic circuit is fitted to the Packard plug. EMC-protection-components are mounted on the plug side, the amplifier on the sensor side. A flexible printed circuit “TAB” connects the sensor with the electronics. The transmitters are designed to have exceptionally good EMC ratings and operate over a wide temperature band, ideal for automotive, hydraulic and refrigeration control applications
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.
The vacuum test pump LR-Cal 2941 is used to generate vacuum (negative pressure) for checking, adjusting and calibrating mechanical and electronic pressure measuring instruments by comparative measurements. These vacuum tests may be carried out in laboratories, workshop or on site at the measuring point. If the instrument to be tested and a sufficiently accurate reference measuring instrument are connected up to the test pump, the same vacuum is applied to the two measuring instruments when the vacuum test pump LR-Cal 2941 is is operated. By comparing the two measure valuses at random pressure values, the accuracy can be verified or the instrument under test can be adjusted. Despite its compact dimensions, the vacuum test pump LR-Cal 2941 is easy to operate and allows for exact generation of the required test vacuum. The LR-Cal 2941 is fitted with a fine adjustment valve for precise adjustment of vacuum. Pressure connection is made with 4 mm hose, a T-piece wich quick-coupling and a piece of hose is included in standard delivery.
The pressure test pump LR-Cal LPP 40 is used to generate pressure and vacuum for checking, adjusting and calibrating mechanical and electronic pressure measuring instruments by comparative measurements. These pressure tests may be carried out in laboratories, workshop or on site at the measuring point. If the instrument to be tested and a sufficiently accurate reference measuring instrument are connected up to the test pump, the same pressure is applied to the two measuring instruments when the pressure test pump LR-Cal LPP 40 is operated. By comparing the two measure valuses at random pressure values, the accuracy can be verified or the instrument under test can be adjusted. Despite its compact dimensions, the pressure test pump LR-Cal LPP 40 is easy to operate and allows for exact generation of the required test pressures; a change-over switch enables the generation of vacuum as well. The LR-Cal LPP 40 is fitted with a fine adjustment valve for generation of high pressure and a precise adjustment of pressures. The reference instrument is screwd directly on the top of the pump and the unit under test is connected by means of the connection tube incorporating an adapter 1/4" BSP female thread (freely rotating), contained in the scope of delivery.
The pressure test pump LR-Cal LPP 08 is used to generate pressure and vacuum for checking, adjusting and calibrating mechanical and electronic pressure measuring instruments by comparative measurements in the low-pressure and vacuum range. The pressure tests may be carried out in laboratories, workshops or on-site at the measuring point.
If the instrument to be tested and a sufficiently accurate reference measuring instrument are connected up to the pressure test pump, the same pressure is applied to the two measuring instruments when the pump is operated. By comparing the two measure values at random pressure values, the accuracy can be verified or the unit under test can be adjusted.
The LR-Cal LPP 08 is a pneumatic pressure test pump for low-pressure ranges up to 8 bar with a change-over switch to vacuum down to -850 mbar. Despite its compact dimensions, the pressure test pump is easy to operate and allows for the exact generation of the required test pressures. The maximum pressure or vacuum achievable depends on the attached test volume. The smooth-running pressure generation and the integrated fine adjustment valve allow a safe and precise setting of very small positive resp. negative pressure values in the range of mbar.
The unit under test and the reference instrument can be easily connected with the supplied accessories.
Included in the scope of standard delivery:
The pressure test pump LR-Cal LPP 700 is used to generate pressure for checking, adjusting and calibrating mechanical and electronic pressure measuring instruments by comparative measurements. These pressure tests may be carried out in laboratories, workshop or on site at the measuring point. If the instrument to be tested and a sufficiently accurate reference measuring instrument are connected up to the test pump, the same pressure is applied to the two measuring instruments when the pressure test pump LR-Cal LPP 700 is operated. By comparing the two measure valuses at random pressure values, the accuracy can be verified or the instrument under test can be adjusted. Despite its compact dimensions, the pressure test pump LR-Cal LPP 700 is easy to operate and allows for exact generation of the required test pressures The LR-Cal LPP 700 is fitted with a fine adjustment valve for a precise adjustment of pressures. The reference instrument is screwd directly on the top of the pump and the unit under test is connected by means of the connection tube incorporating an adapter 1/4" BSP female thread (freely rotating), contained in the scope of delivery.
LR-Cal LPP 60-T Description Pressure comparator LR-Cal LPP 60-T in use with reference pressure gauge LR-Cal TLDMM 2.0The pressure test pump LR-Cal LPP 60-T is used to generate pressures and vacuum for checking, adjusting and calibrating mechanical and electronic pressure measuring instruments by comparative measurements. These pressure tests may be carried out in laboratories, workshop or on site at the measuring point. If the instrument under test and a sufficiently accurate reference measuring instrument (e.g. electronic pressure calibrator LR-Cal LPC 300 or LR-Cal LPC 200, accuracy ±0.025% FS) are connected to the LR-Cal LPP 60-T, the same pressure pressure resp. vacuum is applied to the two instruments when the pump is operated. Despite its compact dimensions, the pneumatic pressure comparator LR-Cal LPP 60-T is easy to operate and allows for exact generation of the required test pressures. A change-over switch enables the generation of vacuum as well. The LR-Cal LPP 60-T is fitted with a fine adjustment valve for the precise adjustment of pressures. The reference instrument is screwed directly on to the top of the pump and the unit under test is connected by means of a connection tube incorporating an adapter 1/4" BSP rotating female (optional 1/4" NPT female) port.
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 pressure test pump LR-Cal 2911 is used to generate pressure for checking, adjusting and calibrating mechanical and electronic pressure measuring instruments by comparative measurements. These pressure tests may be carried out in laboratories, workshop or on site at the measuring point. If the instrument to be tested and a sufficiently accurate reference measuring instrument are connected up to the test pump, the same pressure is applied to the two measuring instruments when the pressure test pump LR-Cal 2911 is is operated. By comparing the two measure valuses at random pressure values, the accuracy can be verified or the instrument under test can be adjusted. Despite its compact dimensions, the pressure test pump LR-Cal 2911 is easy to operate and allows for exact generation of the required test pressure. The LR-Cal 2911 is fitted with a fine adjustment valve for precise adjustment of pressures. Pressure connection is made with 4 mm hose, a T-piece wich quick-coupling and a piece of hose is included in standard delivery.
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.
The 9FLD series is a special version of the 9LD pressure transmitter. The flanged housing can be mounted using an O-ring or welded on. As with all D-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 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.