OEM pressure and temperature converters, digital I2C output — Series 4LD-9LD

Description

With the introduction of the D-line, Keller presents a unique combination of a reliable industrial pressure sensor and a popular microcontroller interface – I²C. Pressure transducers with this interface are usually only available on the consumer market. The housing is typically made of plastic or ceramic, and compensation parameters can be stored in integrated memory. The OEM transducers of the D-line feature an unprecedented innovation – a built-in digital signal processing (DSP) core for compensation and normalization of output values.

Technology

The technology of the 4LD...9LD series is based on the well-known Keller CIO technology – Chip-In-Oil (the letter "L" stands for laser welding of the stainless steel housing) and is equally suitable for low-power transducers (typ. 0.1 µA in standby/sleep mode) and low voltage (power supply: 1.8 ... 3.6 VDC). The housing is hermetically sealed, filled with oil, and together with the glass substrate forms a Faraday cage with feedthrough capacitors around all electronic components. The letter "D" indicates the presence of a digital interface with simultaneous transmission of pressure and temperature information.

Interfaces

The simplest way to connect an OEM pressure transducer to a microcontroller system is to use a digital Input-Output interface. No amplification, no analog or digital conversion, no calibration, no temperature coefficients. Simply put, without any problems.

I²C (Inter-Integrated Circuit) is designed for direct connection between devices on a printed circuit board. It is a BUS system that allows multiple transducers (slaves) to be connected to the same communication line (in this case, it does not mean an industrial bus with the classic large distance between connected devices). Thus, the D series sensors combine a robust, reliable design for critical industrial tasks with a convenient interface for OEM applications.

Values are output in a 16-bit integer format, calculations are set by constants or the contents of the transducer’s memory (two IEEE 754 floating-point values for pressure calculation).

Operating Characteristics

• Very low power consumption, optimized for battery-powered applications
• Hermetically sealed electronic sensor extremely resistant to environmental influences
• Ultra-compact, durable housing made of stainless steel (optionally Hastelloy C-276 or titanium)
• No external electronics for compensation or signal processing
• High accuracy, highest stability over a long time interval, no hysteresis
• Pressure range from 0..1 bar to 1000 bar
• Easy integration into microcontroller-based systems
• Internal separation of the sensitive crystal and signal processing unit provides a high degree of flexibility