The pressure transducers of the 9L series have a compact, robust housing made of stainless steel, giving them outstanding 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, which is 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 .
The pressure transmitters of the 21Y series have no internal seal and a high insulation voltage of 300 VDC, and are extremely resistant to environmental influences. The sophisticated compensation circuit makes it possible to specify a narrow total error band. A wide range of pressure connections and electrical connections are available to choose from.
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.
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 Series 26 Y are used in water level measurements that are price-sen - sitive but still require considerable accuracy. Technology Y-series transmitters have an extremely small temperature error. This is achieved by means of digital compensation of an all-analogue signal path. The gain and the zero point of the gain circuit can be influenced by digital/analogue converters. These receive their numerical values from an EEPROM that is addressed depending on the temperature. A mathematical model for TC zero and TC gain with any order can therefore be determined in the calibration process and stored in the transmitter with a resolution of 1,5 K. The accuracy of the end product therefore essentially depends on the amount of testing and the linearity of the measuring cell. With the Series 26 Y, the monocrystalline silicon measuring cell is reliably protected from the measuring medium by a stainless steel diaphragm. The steel diaphragm itself is protected from mechanical influence by a plastic cap, and has outstanding performance features with regard to accuracy and stability due to its large diameter of 17 mm 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 accuracy thereof is mainly determined by linearity. 120 fields are available, representing a possible temperature range of 180 K. The wider the temperature range, the greater the amount of testing that is needed to minimise the inaccuracy of the mathematical model.
The Series 26 W transmitter utilises the Series 10 piezoresistive capsule, which is housed inside a submersible 316 L stainless steel body as standard. For corrosive applications hastelloy diaphragms and other materials are available as options. Series 26 W vented gauge versions have cable with integral vent tube. These transmitters are fitted with durable PE cable.
This Series is based on the stable, piezoresisitive transducer and a micro-processor electronics with integrated 16 bit A/D converter. Temperature dependencies and non-linearities of the sensor are mathematically compensated. With the READ30 software and the KELLER cable K-107, the calculated pressure can be displayed on a Palmtop, Laptop or PC. The READ30 software also allows the recording of pressure signals and the graphic display on the PC. Up to 128 transmitters can be hooked together to a Bus-system. Programming: 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.
Specifically designed for extended service in sewage lift station environments, the 36 XKY by KELLER features a relatively wide sensing diaphragm yet small overall size. The 36 XKY incorporates a monolithic diaphragm formed from Kynar ® , which combines the non-stick quality of Teflon with superior toughness and abrasion resistance that simplify installation and eliminate the need for bulky and expensive protective cages. The 36XKY utilizes proven piezoresistive silicon measurement technology combined with Kel - ler’s state-of-the-art, microprocessor-based signal conditioning circuitry to provide outstanding accuracy and reliability over a wide compensated temperature range. It is perfectly suited for pump control applications that require standard 2-wire (4...20 mA current loop) or 3-wire (0...10 V) output transmitters. The RS485 interface allows users to scale the analog output to any desired range within the standard pressure range. The 36 XKY is typically suspended into the liquid by a standard Hytrel ® -jacketed cable that is both self-supporting and vented. Optional: Keller’s enhanced lightning protection makes this trans-mitter ideal for installation in areas prone to chronic damage due to transients caused by lightning. Using the Keller CCS30 software and appropriate adapter cable, the user can scale the analog output of the 36 XKY, display and record pressure and temperature readings, and access a variety of other available functions. All of the available functions are defined in the Series 30 Communications Protocol. The CCS30 and Series 30 Communications Protocol are available free of charge from the company website
This pressure transmitter is designed for level measurement in narrow downhole applications where highest accuracy is required. Product Benefits: Only 16 mm diameter, mathematically compensated, programmable, assisting inventory reduction, filtering function 2 ms...30 sec, improved surge protection 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.
Multi-Parameter Probe with Digital Interfaces The 36 Xi W series is built on the latest-generation microcontroller platform, which KELLER has developed to meet extremely high precision requirements and increase compatibility with a wide variety of interfaces. Along with pressure (level) information, digital interfaces also transmit other water parameters such as temperature and conductivity. The 36 Xi W series is based on the proven KELLER 36 X W series using the high-quality 10 L-series pressure transducer. All series X pressure level transmitters feature an RS485 interface, which provide pressure and temperature standard, while versions requiring higher accuraty, temperature or conductivity sensor are available options. Multi-parameter probes fitted with pressure, temperature and conductivity sensors (CTD – conductivity, temperature, depth), are approximately 90 mm longer. Characteristics • Pressure sensor: resolution 5 ppm • Mathematical compensation of nonlinearities and temperature dependencies • Sturdy stainless steel housing (titanium or Hastelloy also available) • Extended lightning protection fitted to the SDI-12 interface as standard • Level measuring ranges from 0…3 m to 0…300 m. Higher ranges are possible using a Sub-Conn® connector • Ultra-high long-term stability
The DCX-16 is an autonomous, battery-powered data collector in a stainless steel housing with a very small diameter of only 16 mm. The housing and the pressure sensor element are completely welded in, so sealing rings are eliminated at this point. In applications where a small probe diameter is an advantage, the logger can record the water level (pressure) and the temperature over long periods. As well as the battery compartment with its double seal, the small-diameter (16 mm) submersible sensor includes electronic circuitry featuring the latest microprocessor technology. It records the pressure and temperature of the medium with high measurement accuracy and resolu-tion, and it uses a mathematical model to correct any linearity or temperature errors made by the pressure sensor. High data reliability is guaranteed thanks to the use of a nonvolatile data memory The various configuration options allow the data logger to be adapted to the measuring point so that only specified events will be detected and stored. Event-controlled recording and loginterval recording can be set independently of one another. In addition, installation data and comments on the measuring point can be stored in the logger. Installation is fast and simple with fixing disks of various sizes which can be fitted as options: these match locking units (caps) from different manufacturers for levels of 1” or more (2” or more with light plummet aperture), so measuring points can be implemented at a fraction of the previous cost. Three versions of the data collector are available: DCX-16 The sensor, electronics and battery are accommodated in one housing. To extract data, the data collector must be removed from the measuring point, and the watertight screw cap that allows access to the read-out plug /interface must be unscrewed. The DCX-16 operates with an absolute pressure sensor. In shallow water, when the influence of air pressure fluctuations has to be taken into account, a second logger (barometric logger, obtainable separately) positioned on the surface of the water must be used to record the air pressure progression. The computer software then calculates the differential pressure or the water level by subtracting the two measured data.
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 Series 46 X combines the ceramic measuring cell for low pressure ranges with the μP-elec- tronics of the digital Series 30 pressure transmitters. The signal values of the pressure- and temperature sensors are determined by a polynomial compensation1). The values can be shown and stored on a PC and can be reprogrammed. A reference tube integrated in the cable connects the referential chamber of the sensor with the ambient pressure.
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.
In the high-precision level probe of the 26X series, the temperature dependence and nonlinearity are precisely compensated for in the microcontroller by means of a mathematical model. In addition to the RS485 interface, the measurement results can also be output via the integrated D/A converter as a rangeable analog signal. Extended lightning protection is also available as an option.
The pressure transmitters of the 7LD 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 high-precision multi-parameter probes of the 36XiW-CTD series measure conductivity and temperature as well as pressure, along with the depth of bodies of water. Temperature dependence and nonlinearity are precisely compensated for in the microcontroller by means of a mathematical model. The integrated Pt1000 achieves an accuracy of ±0,1 °C, and the conductivity can be measured at ± 2,5% of the selected range (0,2 / 2 / 20 / 200 mS/cm). The sensors can be supplied with either an RS485 or SDI-12 interface. Extended lightning protection comes as standard with the SDI-12 and is available as an option for the RS485 interface.
The compact LEO2-Ei digital manometers are budget-friendly and provide high accuracy. 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).
Intrinsically safe – suitable for use in explosive atmospheres.
The high-accuracy LEO-Record-Ei digital manometers can record pressure and temperature autonomously for long periods thanks to their memory function. The data logger can be connected to a computer via the RS485 interface for configuration and for reading out the recorded data. The current pressure value can be displayed in a wide variety of units of pressure. Power is supplied by a high-quality 3,6 V lithium battery.