Electricity + Control March 2018

round up

TEMPERATURE MEASUREMENT

New microprocessor controlled instrument range

the primary reading for remote monitoring purposes. Also fitted are two digital in puts operating on either closed or open contact which allow the instrument to be triggered by No Flow, Low Tank Level, Interlock or Off-line functions that forces the relays to deactivate and the current output to a pre-defined state. All the individual controller variants are compatible with LTH’s ex- isting measuring sensors and electrodes offering full compatibility with existing installations.The BXD17 series will be a low cost series on instruments to replace the BC9, BP9, BR9, and CDM9 series of instruments and to provide a range of low cost surface, panel and pipe mounting instruments. The enclosure should be designed as a panel / surface mount dual version enclosure possibly suited to a 144 x 144 mm front with a 138 x 138 mm cut out and ideally will be the same enclosure used for the future HCT82 two wire series of transmitters. Consideration should also be given that PCB’s should be designed so that they can be used for the panel and surface en- closures. The following measurement parameters are required: Contacting Conductivity, Electrodeless conductivity and pH / Redox +Temperature and Dissolved Oxygen (Optical) to follow later. We should consider whether we have a common base PCB with plug in measurement cards or whether each measurement should have a different PCB. The design should be kept as simple as possible with sensor cable lengths limited to 30 metres only. Enquiries: Email VickiB@tempcon.co.za

The BXD17 is a microprocessor controlled instrument range offering individual con- trollers for the measurement parameters Electrodeless (Inductive) and Contact

Conductivity, p/HRedox and dissolved Oxygen. To achieve this the instrument utilises a clear multifunction LCD to display the primary reading and temperature, show operational status and to provide an intuitive user interface. As standard the instrument is simple to install with a new custom 144 x 144 mm IP66 rated Wall-mount instrument, however with the addition of a suitable mounting kit it can either be installed as a Panel-mount or Pipe-mount instrument. Available from Temperature Controls , the instrument has two onboard volt-free normally open-relays with adjustable setpoint val- ue and hysteresis. Either one can be set to activate on a High, Low or Band operation allowing the instrument to be used in a variety of dosing and or control applications. Additional setpoint functions in- clude delayed activation and dose alarm timer, whilst the status of the relays can be seen via the main screen of the instrument. The set points relays may also be given the function as a clean initiator to provide automatic sensor cleaning, the clean duration, recovery time and interval period all programmable. Additionally, the instrument features one industry standard, iso- lated, 0/4 -20 mA current output that features adjustable scaling and selectable on-error states, allowing the instrument to transmit After time, temperature is the second most measured physical unit. In production as well as in quality control and maintenance, temper- ature represents an important indicator of product quality or equip- ment conditions. Users struggling with large maintenance bills for thermocouples, or the plant downtime required to replace regular contact-type temperature probes, need look no further than non-con- tact Infrared (IR) temperature measurement devices.There are many advantages when using IRthermometers: • Fast response time (ms range), user gets more information per time period • Measure objects that move, rotate or vibrate (e.g. web pro- cesses or any moving process) • Measure high temperatures up to 3 000ºC. Contact probes will not work or have a short lifetime • No mechanical damage or contamination of the surface (food, pharmaceuticals, painted surfaces, soft plastics etc) • No influence of objects with high thermal-conductivity where object temperature would change if contacted (e.g. glass, wood, small or very thin objects) To ensure an accurate repeatable measurement you must consider certain conditions: • There has to be direct line of sight between the sensor and the object • The optics of an IR thermometer needs to be protected against dust or condensation • IR thermometers measure surface temperatures and the ability to emit thermal radiation depends on the kind of material and especially on the surface finish.

Advantages of non-contact temperature measurement

Recently the IR-sensor market has seen two major trends: First, IR-thermometers are significantly lower in cost. The most expensive parts of an IR thermometer are the lenses and detectors. New lens ma- terials, technologies and mass production of IR-detectors for

consumer products have resulted in lower prices for these two important components. Together, with the increased demand for industrial IR-thermometers, high volume production of standard sensors has resulted in greater manufacturing efficiency for the IR-thermometer manufacturers. Second, IR Sensors are becoming smaller in size. In the past, the measurement of low temperatures made it necessary to use fast lenses with relatively large diameters in order to capture enough emitted energy. Progress in detector technology and the use of bet- ter detector performance, together with improved low noise ana- logue preamplifier techniques have helped reduce the dimensions of the IR-sensing head dramatically. Because the newer sensors have greater response characteristics they require less energy to achieve a usable signal. As a result, lenses can have smaller diameters. At R&C Instrumentation we cover the full range of IR temper- ature measuring devices. Our Raytek range of portable units cover temperatures from -50 to 3 000ºC with Raytek being one of the first to introduce this technology and now a recognised industry standard. Enquiries:Tel. 086 111 4217 or email info@randci.co.za

20 Electricity + Control

MARCH 2018