Niels Aakvaag

Wireless communication in process control loop: Requirements analysis, industry practices and experimental evaluation

Wireless communication is already used in process automation for process monitoring. The next stage of implementation of wireless technology in industrial applications is for process control. The need for wireless networked control systems has evolved because of the necessity for extensibility, mobility, modularity, fast deployment, and reduced installation and maintenance cost. These benefits are only applicable given that the wireless network of choice can meet the strict requirements of process control applications, such as latency. In this regard, this paper is an effort towards identifying current industry practices related to implementing process control over a wireless link and evaluates the suitability of ISA100.11a network for use in process control through experiments.

Towards the development of a SIL compliant wireless hydrocarbon leakage detection system

Wireless communication is one of the fastest growing technologies in process automation and now targets main stream applications. One such application is a safety application; it is unique in its own rights, as any problem with safety related equipment, network or system can compromise on-site safety. For the wired networks which serve safety applications, they are designed to ensure QoS. Therefore, controlling delay, jitter, packet loss rate and bandwidth is critical. To achieve the same performance over an envisioned wireless network with shared communication medium, various problems are to be dealt with. In this regard, this paper is an effort towards the design of a SIL compliant solution. Hence, this paper addresses the key constraints of the wireless technology and demonstrates the proof-of-concept through a field trial.

Wireless gas sensing in South African underground platinum mines

Approximately 70% of South African mines are classified as fiery, where methane gas potentially could cause explosions. The number of flammable gas reports and accidents are increasing steadily for both gold and platinum mines. However, there is less awareness of the hazards of methane in hard rock mines (gold and platinum) than in coal mines. Currently, there is no wireless real-time gas sensing system used in South African hard rock mines. The main objective of this work is to investigate the possibility of using a wireless gas detector called GS01 in underground mines. Several experiments have been conducted to evaluate the GS01 performance, accuracy and the ability to communicate in underground mines. The results demonstrate the suitability of using GS01 in such harsh environments. A second motivation for the work was to evaluate the performance of wireless communication using different frequencies.

Wireless Infrared Gas Sensor

Infrared hydrocarbon gas detectors are essential for safety, but the requirement for cabled power complicates installation. A new low-power optical design based on a micro-opto-electromechanical system gives several years of reliable battery operation.

Trial Implementation of a Wireless Human Machine Interface to Field Devices

In order to configure field instruments today, it is necessary for the operator to approach each device and program it using the human-machine interface (HMI) placed on the instrument. This paper describes a demonstrator concept of how to use wireless communication and a portable device to achieve this at a distance, and simultaneously with several instruments. The major problem that has to be overcome in order to use wireless communication is the severely limited power available. The instrument in question is running on a 4-20mA current loop, and the power for the wireless communication comes from the available internal current in the instrument, in this case limited to 400muA at 3.0V. Since the available power is constrained, the radio is duty cycled so that it mostly sleeps, and transmits only when there is power available.