Maintaining the accuracy of spectral analysis systems deployed for continuous monitoring applications in harsh environments is challenging. Temperature and humidity fluctuations, mechanical vibration and operational stresses can compromise spectrometers at the core of analytical instruments leading to measurement drift, increased maintenance, and compromised and so unreliable analysis. Function in the stable conditions of a test lab is a very different proposition to reliable operation in the field.
The need to provide a ruggedised product capable of precise measurement when deployed for continuous use, for example air quality or gas monitoring on chimney stacks, has inspired OtO Photonics to evolve the SmartEngine spectrometer series. All versions of SmartEngine offer superior performance compared to products from well-known competitors. Available in the UK and Ireland through AP Technologies, SmartEngine represents a highly effective solution to industrial spectral analysis demands.
Innovative Engineering Offers a Compact and Robust Design
Innovative Engineering Offers a Compact and Robust Design
At the heart of the SmartEngine's reliability lies its compact, rigid optical bench design. Unlike many spectrometers that are susceptible to environmental disturbance, SmartEngine fully optimises materials and manufacturing processes specifically for industrial resilience. The optical bench provides a stable platform that maintains excellent thermal, shock, and vibration performance whilst delivering high optical resolution and sensitivity, low stray light, and fast response times.
OtO Photonics’ decades of module design means that they are perfectly positioned to design an optical system that offers reliable service, over a long product lifetime, without compromising accuracy of analysis. There is a recognition that spectrometers must function reliably in outdoor monitoring stations where conditions are far from benign as well as on factory floors.
A Breakthrough in Wavelength Stability and The Benefits for Real World Applications
Following an ethos of continual improvement, the latest generation of SmartEngine spectrometers have been developed to address the persistent and stubborn spectral analysis challenge of wavelength drift. The new generation demonstrates increased wavelength stability with this advance being characterised by:
- Material selection: The careful optimisation of the grating substrate and lens materials minimises thermal expansion coefficients, with the result that temperature variations don't translate into optical misalignment. This change has positive implications for long-term thermal stability and so measurement consistency.
- Advanced bonding techniques: Further improved bonding methods offer enhanced stability of optical components when under physical stress such as shock and vibration or thermal variation, so avoiding the gradual weakening of the device that can undermine calibration over time.
- Mechanical structure optimisation: OtO have focussed on refining the mechanical design to create an optimally stable structure that resists deformation under varying loads and environmental conditions.
These advances have been implemented in mass production and is already deployed by large OEM customers, with annual demand exceeding 1,000 units. This large-scale deployment provides compelling evidence of the technology's reliability in demanding applications.
Practical Implications for Gas Sensing Applications
The enhanced wavelength stability and further improved ruggedisation proves particularly valuable in gas sensing applications, where accuracy is critical to both safety and regulatory compliance. Whether monitoring environmental conditions, ensuring industrial safety, or controlling processes, the ability to accurately identify and quantify gases relies on consistently accurate spectral analysis.
When used for gas sensing, any drift in wavelength calibration can lead to misidentification of gases or incorrect concentration readings. In safety-critical applications, such errors can have serious consequences. The improved stability SmartEngine provides the confidence that measurements will remain consistent and trustworthy over extended periods, even in challenging environments.
Consider for example gas monitoring systems with sensors deployed in petrochemical refineries. In such circumstances, reliable operation notwithstanding temperature swings, vibration from machinery and the impact of varying weather conditions is essential. The SmartEngine's rigid optical bench maintains alignment and calibration under these conditions, reducing the need for frequent recalibration and minimising system downtime.
Performance Without Compromise
The SmartEngine's robustness doesn't come at the expense of analytical performance. The system maintains high optical resolution (down to 0.2nm) and offers high-pixel modes with less than 0.06nm per pixel, enabling the resolution of narrow spectral lines essential for distinguishing overlapping absorption features.
SmartEngine is suitable for a wider range of applications. Low stray light performance (specification <0.2%, typically 0.15%) through the use of patented internal coatings, selection of optical components and careful cavity design ensures accuracy at low counts whilst industry-leading linearity of 99.5% ensures accuracy over a wide signal range. Fast response capabilities, with integration times as short as 0.1ms (depending on choice of sensor, or 1.7µs in FX2 models), enable high-throughput measurements – suitable for manufacturing production line applications.
The SE-FX2 models, utilising high-speed, low-power consumption processors that reduce internal heating and improve thermal stability are especially suitable for applications requiring rapid detection or high throughput, such as LED testing or real-time process monitoring.
Comparison With a Spectrometer From a Leading Competitor
Back-to-back testing of the SmartEngine SE2020 model with a model from a well-known competitors featuring the same linear sensor demonstrates the superiority of the SmartEngine:
| PARAMETER |
OtO SE2020 (50µm Slit Width) |
COMPETITOR MODEL (25µm Slit Width) |
||
| Specification | Tested Value | Specification | Tested Value | |
| Resolution (nm) | 1.9 | 1.62 | 1.5 | 1.68 |
| Wavelength Accuracy (nm) | 0.4 | -0.09 | 0.4 | -2.05 |
| Sensitivity (Visible Range) | ~ | 1.9 | ~ | 1.00 |
| Stray Light (435 - 450nm) | <0.15% @ 450nm | 0.13% | <.125% @ 435nm | 0.16% |
| SNR | 250 | 250 | 250 | 250 |
| Linearity | 99% | 99.5% | 99% | 93% |
| Residual Error | 1% | 0.5% | 1% | 7% |
- Models chosen based on similar data sheet figures for FWHM resolution. The SE2020 achieved the figure of 1.62nm with a 50µm slit where the competitor’s model was outside the published specification at 1.68nm FWHM using a 25µm slit width.
- The wider slit width possible due to SmartEngine’s superior optical design results in 1.9x sensitivity AND better resolution.
- Alternatively, if the SE2020 was specified with 25µm slit width resolution would be ~1nm FWHM.
The same testing, carried out by an OtO customer, demonstrated superior wavelength drift and FWHM resolution under temperature and humidity cycling, shock and vibration.
Flexible Integration
OtO Photonics offer a number of product variants, so allowing for flexibility in terms of integration. Available with a wide and growing choice of sensors, slit sizes, and grating configurations, SmartEngine can be optimised for specific applications. This flexibility, combined with USB and UART communication with multiple I/O options, simplifies integration into existing systems.
For development and testing, OtO offers the PKG Spectral Measurement Kit, which provides a complete measurement solution including spectrometer, light source, and accessories in a rugged, waterproof case. This approach offers system developers the ability to use OtO spectrometers for prototype development and reduces the complexity of initial system design.
The Value of Reliable Spectral Analysis
The SmartEngine represents more than just a component upgrade. Extended product lifetime, low maintenance requirements, improved measurement consistency, and enhanced operational reliability translate directly into lower total cost of overall system ownership and improved customer satisfaction. When module reliability is often a critical and overarching underlying requirement when selecting a spectrometer, these advantages provide genuine strategic value.
The SmartEngine's evolution demonstrates how thoughtful engineering can resolve the traditional trade-off between precision and robustness. For manufacturers seeking to enhance their systems with reliable spectral analysis capabilities, it offers a solution the comparative advantages of which it’s hard to ignore.
For more information on how SmartEngine can enhance your spectral analysis applications please visit the Product Page and our "How to Specifiy SmartEngine" support page, or contact AP Technologies to discuss your specific requirements and arrange a demonstration.
| To discuss your spectral analysis application and requirements contact Martin at AP Technologies |
