PyrIQ® – Flexible Detectors for Gas and Flame Analysis
At PyrIQ® digital detectors amplification, signal conditioning, and analog-to-digital conversion are all performed within the detector housing by an application-specific integrated circuit (ASIC). This allows
Easy system integration,
Improved electromagnetic compatibility (EMC) and
Full flexibility in configuring detector parameters (wide dynamic range).
Conventional pyroelectric detectors provide an analog output signal that has already been amplified internally. Users must process this signal for further evaluation, for example by limiting the bandwidth or adapting it to the voltage range of the digitizer. Only after this “signal conditioning” can analog-to-digital conversion outside the detector, as well as the subsequent processing of the digital signals on the computer, be performed.
Easy Integration through On-detector Digitalization
The PyrIQ® series detectors take a different approach: amplification, signal conditioning, and analog-to-digital conversion are all performed within the detector housing by an application-specific integrated circuit (ASIC). The 16-bit digital signal provided by the ASIC can then be read out at sampling rates of up to 1 kHz via a standard communication interface (I2C) and subsequently processed directly by a microcontroller. This allows, among other things, the feedback resistance and capacitance of the analog front end to be adjusted for each individual channel, thereby optimizing sensitivity and the signal-to-noise ratio.
The digital output signal makes it significantly easier to integrate PyrIQ detectors into systems. The spatially concentrated, shielded signal processing within the detector reduces the number of interference-prone analog signal paths, thereby creating a robust foundation for use in demanding EMC environments.
In addition, the signal processing can be flexibly adapted to the specific application at any time in terms of electrical amplification and filtering. Users therefore have the opportunity to influence the properties of the detector from the development phase through to the final product. With the PyrIQ® Evaluation Kit provided by InfraTec, it is possible to carry out initial tests of the detectors with a digital interface without having to provide one’s own software, firmware, or test circuits. Using the accompanying software from InfraTec, the detector and IR source parameters can be individually adjusted via an intuitive graphical user interface.
Advanced Features for Precise Measurements
The ASIC's clock frequency can be supplied externally via the clock pin to generate a timing signal with a high-precision sampling rate. In gas analysis in particular, this simplifies the synchronization of the emitter and detector clocks. A temperature signal, which is required for proper calibration in NDIR measurements, for example, is provided by a temperature sensor integrated into the detector.
Another distinctive feature of PyrIQ detectors is the “Fast Recovery after Saturation” function. In the event of overdrive caused by a malfunction – such as extreme temperature fluctuations or mechanical stress – the analog input stage is automatically reset for a brief moment. This results in faster recovery of the detectors.
Field application: Exhaust Gas Monitoring with PyrIQ Detectors
The LRD-3824 detector from the PyrIQ family is used, among other things, in various emission measurement devices for gas and smoke analysis. This enables, for example, the measurement of CO, CO₂, and hydrocarbon concentrations (NDIR), monitoring of vehicle exhaust emissions, and flame detection.
Several factors were decisive for users in their decision to choose the InfraTec product:
Easy development thanks to digital output
Individual adjustment of the detector signal amplification for each spectral channel, depending on the measurement effect
Three measurement channels and one reference channel in a compact housing, combined with large pyroelectric elements for a high signal output
Advantages and Benefits of PyrIQ Detectors with Digital Interface
Complex signal processing steps are eliminated due to the I2C interface and the integrated analog-digital converter.
Individual adjustment of the detector signal amplification for each spectral channel, depending on the measurement effect
The entire signal conversion is spatially concentrated and shielded and thus less susceptible to electromagnetic radiation.
Converts the analog signal, which can be filtered and amplified in several stages, directly into a digital signal with a 16-bit resolution.
