Sentinel Gas Detection system takes mine safety to a higher level

A case study about the development of a gas detection system and support equipment and the integration into the Schauenburg Flexaducx Mine-Wide Integrated Monitoring and Control System

By Tobie van Loggerenberg, Business Development Director, Parsec

Safety, where people are involved, is very important. This is even more important for the mining industry where the mines are legally obliged to guarantee the safety of their employees despite the numerous risks associated with the working environment.  An integrated safety system ensures information sharing between sub-systems enabling effective warning and control without delay.

Schauenburg Flexadux (, a company specialising in the supply of safety equipment for mining had a concept in place of a distributed monitoring and control system called MIMACS (Mine-Wide Integrated Monitoring and Control System) but lacked  a modern automated solution for gas detection which is required to meet the SANS 1515 standard as adopted by the SABS in 2006. The company approached Parsec to develop such a system and ensure compliance with the SABS standard.

This case study describes the development of the Sentinel GDI (Gas Detection Instrument) for detecting and reporting of hazardous gas concentrations present in work areas in mines. The device collects data from various on-board sensors, displays the concentration values on a built-in screen and logs it to an internal non-volatile memory. This data can be retrieved from the instrument by means of a wireless communication link. Sentinel Gas detection system-1

The development of the prototype by the previous development partner was plagued by many problems. This put Schauenburg in a difficult position as their marketing efforts for the new GDI had created anticipation in the industry and lined up clients, but the product was not ready. The opposition also had new instruments in the pipeline and Schauenburg was pressured to not only keep their market share, but also expand on it.

The objective for Parsec was to develop and certify the GDI in as short a time frame as possible, produce a design with maximum flexibility and have remaining capacity for future expansion.

Due to short timescales, the project was approached concurrently from three sides. Firstly, the instrument itself needed redesign in order to achieve SABS certification. Secondly, the support equipment which addressed charging, calibration, testing and configuration was also required during the certification process. Thirdly, the software for the instrument, tester/calibrator and configuration was needed at the end of the certification period.

Temporary low level software was used during certification in order to verify the critical gas measurement hardware also giving the software team more time to develop the final application with a friendly, aesthetically pleasing user interface with extensive capabilities.

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Major Challenges to overcome from the prototype baseline


Parsec started with a partly developed prototype baseline. The mechanical parts were already in an advanced stage of development and it was decided not to make dramatic changes to the mechanics due to negative knock on effect of costs and time to market. The electronics were plagued by various issues like inefficient power conversion, excessive temperatures on the charge stations, non-functional wireless communications, high current spikes blowing the Intrinsic Safety fuses and noisy analogue circuits.


The battery life that previously lasted less than eight hours on a full charge was extended to eighteen hours with all sensors fully activated and the display continuously switched on. This ensures the safety of personnel even in the event that a double shift needs to be completed underground.

A configurable analogue-front-end was implemented making it possible to accommodate different configurations of gas sensors without the need for physical change of components on the PCB.

Wireless communications by means of an 868 MHz radio makes it possible to exchange data with a management server. Logged data can now be uploaded to the server from where reports are generated on request. Software and setting can also be managed and downloaded to an individual or multiple instruments simultaneously.

Contactless inductive charging runs reliably and fully charges a drained battery in less than eight hours.

Automatic calibration and test stations were implemented requiring no user intervention of the process. Multiple stations in a single area testing multiple instruments simultaneously is now possible. Log and upload of results from the test stations to the server makes it possible to audit test & calibration procedures on any instrument at any time.

The instrument achieved SANS 1515 certification on 23 December 2011.

Parsec prides itself on its ISO9001 accredited processes which guided this project through the different phases of its lifecycle. Regular communication with the customer also proved helpful to manage expectation on progress and delivery.

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Through developing the Sentinel GDI and support equipment, Parsec learned valuable lessons including the importance of de-risking throughout the project lifecycle. It is important to validate each sub-system as soon as possible and identify potential problems.   It has proven our ability to supply a customized all-inclusive solution to our customer. The company is well positioned to be involved in the subsequent development of mine related safety equipment and infrastructure.

About Parsec

Parsec is a technology force capable of developing, manufacturing and supplying state-of-the-art embedded solutions in the form of sub-systems or products to a wide spectrum of clients in the global defence / aerospace, telecommunications, industrial market and mining sectors.

Our purpose is to enhance the competitiveness of our partners and clients by enabling them to remain focused on their core competencies, while relying on Parsec’s expertise, capabilities and value added services.  We therefore promote a strategy to partner with other product or service companies that outsource their design and/or production requirements to Parsec.