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.
Digital Output of Transmitter: This high precision of 0,01 %FS is available as an option (the standard Series 33 X has an accuracy of 0,05 %FS). These Series are based on the stable, floating piezoresisitive transducer and the newly developed XEMICS micro-processor with integrated 16 bit A/D converter. Temperature dependencies and non-linearities of the sensor are mathematically compensated. Transmitter with Analog Output: Integrated in the XEMICS processor is a D/A converter of 16 bit for analog signal outputs of 4…20 mA or 0…10 V. The output rate is 400 Hz. The accuracy is diminished by this converting process by 0,05 %FS. The digital output is available on all transmitters with analog output. Programming With the KELLER software READ30 and PROG 30, a RS485 converter (i.e. K102 or K107 from KELLER) and a PC, the pressure can be displayed, the units changed, a new gain or zero set. The analog output can be set to any range within the compensated range. Accuracy and Precision “Accuracy” is an absolute term, “Precision” a relative term. Dead weight testers are primary standards for pressure, where the pressure is defined by the primary values of mass, length and time. Highest class primary standards in national laboratories indicate the uncertainty of their pressure references with 70 to 90 ppM or close to 0,01%. Commercial dead weight testers as used in our facilities to calibrate the transmitters indicate an uncertainty or accuracy of 0,025%. Below these levels, KELLER use the expression “Precision” as the ability of a pressure transmitter to be at each pressure point within 0.01 %FS relative to these commercial standards. The transmitter’s full-scale output can be set up to match any standard of your choice by correcting the gain with the PROG30 software.
The Series PRD-33 X was developed for applications that require a high accuracy differential pressure measurement together with high overload resistance in differential pressure ranges as low as 350 mbar. The Series PRD-33 X is the result of ongoing development of the KELLER PD-33 X differential pressure transmitter. Thanks to a second integrated pressure sensor, the line, or common mode, pressure can now be measured along with the differential pressure, resulting in several notable features not found in traditional differential pressure transmitters. For example, compensation for line pressure effect is now accomplished during factory calibration. Moreover, both differential and line (absolute) pressure may be read by the user. In addition, the PRD-33 X features high differential overload resistance; e.g., ± 35 bar with a differential measuring range of only 350 mbar (100:1). The internal differential pressure sensor element is isolated from the High (+) side media by a compliant stainless steel diaphragm, while the Low (-) side media impinges directly on the back side of the silicon measuring cell. Also isolated from the High (+) side media is the line (absolute) pressure sensor. The floating sensor assembly guarantees maximum decoupling from external mechanical forces. Another notable feature of the Series PRD-33 X is the robust digital RS485 bi-directional communication interface. Information such as serial number, pressure range, filter settings and process values for both differential and line (absolute) pressures and their temperatures are easily obtained. This combination of features enables certain measurements not possible with traditional differential pressure transmitters. For example, filling levels in liquefied gas storage tanks, including oxygen, nitrogen, carbon dioxide and argon can now be measured safely, accurately and at reasonable cost.
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 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).
In the 23SX series high-precision pressure transmitters, temperature dependencies and non-linearity are precisely compensated for by means of a mathematical model in the microcontroller. In addition to the RS485 interface with Modbus RTU protocol, there is also the option of outputting the measurement results as a scalable analogue signal via the integrated D/A converter. The fully welded construction without internal seals is suitable for dynamic applications. Only stainless steel is in contact with the media.
The pressure transmitters of the 21C series with ratiometric 0,5...4,5V output combine chip-in-oil measuring cells with conventional electrical connections and pressure connections, making them ideal for industrial use. The transmitters are extremely resistant to environmental influences and deliver accurate measurement results over a temperature range of -40 °C to 125 °C.
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.
In the 23SXc series high-precision pressure transmitters, temperature dependencies and non-linearity are precisely compensated for by means of a mathematical model in the microcontroller. With the CANopen interface, KELLER offers a highly accurate pressure transmitter that is optimally suited for a wide variety of automation solutions. The fully welded construction without internal seals is suitable for dynamic applications. Only stainless steel is in contact with the media.
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.:
Digital manometers in the dV2 series from KELLER have versatile configuration options, with a max/min and zero function. The integrated microcontroller makes it possible to achieve [Genauigkeit|accuracies]] of up to 0,1 %FS. Larger unit quantities can also be programmed with tailored device functions in preparation for their subsequent use. The dV2 manometers are available with a range of housing designs and process connections, and can also be obtained as an OEM module.
The pressure transmitters of the 9LD 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 highly dynamic and compact 21PHB pressure transmitter is suitable for use in liquids and gases, and can process pressure changes with a bandwidth of 20 kHz. This is achieved by means of the continuous analog signal that is adjusted by a digital circuit in real time and is amplified to a standardised 0...10V signal. The miniature sensor head with a fine M6 thread can withstand temperatures of up to 100 °C and is overload-proof up to a magnitude of four times the measuring range.
The pressure transmitters of the 22S series were designed for use in automotive and industrial applications. They are homologated and every one of their elements has been configured for optimum reliability. In this steel version of the 22 series, all parts that come into contact with media are made of stainless steel (AISI 316L).
The programmable pressure switches of the 22-PS series are encased in a compact yet robust steel housing and are available with PNP or NPN wiring. The pressure switches can be supplied pre-configured at the customer's request. With the aid of the dV22-PP programming unit (available for purchase separately), the two switch outputs can be programmed at any time to be normally closed or normally open at a range of switching points with a window or hysteresis function.
The pressure transmitters of the 23SY-Ei series are designed for elevated requirements in industrial applications. Thanks to its modular concept, this series is highly flexible and makes it possible to realise customer-specific requirements in very little time. The sophisticated compensation circuit makes it possible to specify a narrow total error band.
Intrinsically safe – suitable for use in explosive atmospheres.
The pressure transmitters of the 25Y-Ei series with a front-flush separating diaphragm are designed for elevated requirements in industrial applications and are supplied with a G1/2" male pressure port. Thanks to its modular concept, this series is highly flexible and makes it possible to realise customer-specific requirements in very little time. The sophisticated compensation circuit makes it possible to specify a narrow total error band.
The pressure transmitters of the 33X-Ei series use digital compensation with a mathematical model to achieve exceptional accuracy of 0,05 %FS – in the temperature range from 10 to 40 °C, this value even corresponds to the total error band. Additional measurements and selections can optionally be used to achieve a precision (and also, if calibrated in an accredited test laboratory, an accuracy) of 0,01 %FS. In addition to the digital RS485 interface, the X-line transmitters have a rangeable, analog current or voltage output.
The front-flush pressure transmitters of the 35X-Ei series use digital compensation with a mathematical model to achieve exceptional accuracy of 0,05 %FS – in the temperature range from 10 to 40 °C, this value even corresponds to the total error band. In addition to the digital RS485 interface, the X-line transmitters have a rangeable, analog current or voltage output.
The differential pressure transmitters of the PD-33X-Ei series are suitable for 'wet/wet' applications. They have a single silicon diaphragm in their interior, which is pressurised from both sides and measures the pressure difference directly. This design enables them to measure small pressure differences even at an extremely high line pressure. The transmitters use digital compensation with a mathematical model to achieve exceptional accuracy of 0,05 %FS – in the temperature range from 10 to 40 °C, this value even corresponds to the total error band.
The capacitive pressure transmitters of the 41X-Ei series are designed for measuring relative pressure values in the mbar and µbar range. They use digital compensation with a mathematical model to achieve an accuracy of 0,1 %FS – in the temperature range from 10 to 40 °C, this value even corresponds to the total error band. In addition to the digital RS485 interface, the X-line transmitters have a rangeable analog current or voltage output.
The differential pressure transmitters of the PD-39X-Ei series measure the pressure difference indirectly using two absolute pressure sensors. The dual-sensor design with numerical differential formation also outputs the line pressure values via the digital RS485 interface and guarantees a high overload resistance. The additional analog current or voltage output is primarily used to output the differential pressure range, which is freely rangeable within the line pressure range.