Electricity + Control February 2018

round up

SENSORS, SWITCHES + TRANSDUCERS

Pyrometer with automatic spot finder function

opens up new fields of applica- tion, for example, in mechani- cal engineering or multi-sensor applications,” explains Torsten Czech, Head of Product Management at Optris. Motorised focus facilitates installation and use Both the Xi 80 and Xi 400 models are equipped with a motorized focus enabling remote focusing via the free PIX Connect software. The sensors offer a resolution of up to 382 x 288 pixels, a frame rate of up to 80 Hz and a measuring spot to distance ratio of up to 390:1. Xi devices are calibrated for temperature measurements within a range from -20 to 900°C. Enquiries:Tel. +27 (0) 10 595 1831 or email sales@instrotech.co.za

Instrotech offers the latest in Optris infrared innovation, the Xi series, a fusion between a robust, compact pyrometer and an advanced IR camera. The integrated spot finder function enables accurate temper- ature measurements in moving objects without having to readjust the sensor. Sensor adjustment takes place autonomously, that is, without having to establish a connection with a PC. In addition to a direct 0/4- 20 mA analog output, the devices also offer users digital interfaces such as Ethernet or RS485. An external processing interface permits the further processing of up to nine freely definable analog outputs, making it ideal for OEM applications. “With the Xi series, Optris is launching a semi-autonomous sensor which, in addition to traditional PC and software-based operation, also works as a smart pyrometer with analogue or digital outputs that seeks the target on its own. This

When to use fibre optics for photoelectric sensing

rugged, and perform reliably in extreme temperatures. Sheathing materials such as polypropylene, Teflon®, and nylon are used to shield both plastic and glass fibre optic assemblies in harsh environments. Fur- thermore, optical fibres are low in mass, enabling fibre optic assemblies to with- stand high levels of vibration and mechan- ical shock. 3. Flexibility to meet a wide variety of application requirements Some fibre optics have flexible probes that can be optimally “shaped” to the physical and optical requirements of a specific ap- plication. Considerations for choosing a fibre optic sensing technology There are very few disadvantages to using a fibre optic sensing system, but there are a few considerations to keep in mind when choosing a sensing technology: costs, sensing range, and excess gain. • Sensing system cost: Fibre optics adds cost to a system, since a fibre optic as- sembly is always an extra part in addition

In some sensing situations, space is too restricted or the environment is too hostile for most sensors. Fibre optics, transpar- ent strands of glass or plastic, is used to conduct light energy into and out of such areas. This article describes advantages, considerations, and common applications for fibre optic sensors. Fibre optics has many advantages in photoelectric sensing, including their size, flexibility, and ability to withstand challenging environments where other sensors may not be an option. The small size and flexibility of fibre optic assemblies allow positioning and mount- ing in tight spaces. Plastic fibre optic as- semblies are usually single strands of opti- cal fibre. They can be routed into extremely tight areas. Plastic fibres also survive well under repeated flexing. Pre-coiled plastic fibre optics is available for sensing applica- tions on reciprocating mechanisms. 1. Compact size for tight sensing locations

to a basic photoelectric sensor. Costs must be weighed against the benefits to determine whether fibre optics is the right solution for an application • Sensing range and excess gain: A large percentage of the sensing light energy is lost when coupling light to and from a fibre. Fibres also attenuate some light along their length. As a result, sensing ranges are shorter and excess gain levels are lower than self-contained sensors Typical applications for fibre optics Because of their inherent attributes, fibre optics are ideal in the following applications: • Punch presses • Vibratory feeders • Conveyors • Pill counting • Small object detection • Ovens • Semiconductor processing equipment • Robotic arms and moving machines Enquiries: BrandonTopham. Tel. +27 (0) 11 453 2468 or email brandon.topham@retautomation.com

2. Reliable performance in harsh or explosive environments Fibres can be constructed to survive in areas of cor- rosive material or extreme moisture and are immune to electrical noise. Fibre optics contains no electrical circuit- ry and has no moving parts, so they can safely “pipe” light into and out of hazard- ous sensing locations. In addition, most glass fibre optic assemblies are very

24 Electricity + Control

FEBRUARY 2018