Programmable temperature transmitters with Modbus
September 2005
Temperature Measurement
Programmable transmitters have many advantages such as digital design, catering for any temperature range, ability to re-program sensor inputs and a range to suit any application. However, these transmitters normally have only a 4 to 20 mA output signal. Unitemp is now offering a range of transmitters with a Modbus output signal, thus, ensuring easy integration into PLCs and scada systems.
Conventional temperature transmitters are based on an analog design and can only handle one temperature range and one sensor (eg, a Pt100 with a temperature range of 0 to 100°C). They are also subject to drift and the potentiometer slides out of calibration due to vibration.
The newer programmable temperature transmitters are based on a digital design and thus drift has been greatly reduced. They can handle all temperature ranges, any sensor and can be re-programmed via a PC to suit every new application (eg a Pt100 with a temperature range of 0 to 100°C or a thermocouple with a temperature range of 100 to 200°C). However, these transmitters only have 4 to 20 mA output signals and cannot directly communicate with PLCs or scada systems.
UniTemp offers the new Novus DigiRail family with Modbus communications. Included in this range are units with a relay output, a digital counter and a programmable module for temperature and analog signals. In these modules the conventional 4 to 20 mA output is replaced by Modbus communications. This allows easy integration directly into PLCs or scada systems. Cabling is done on an RS485 basis allowing distances up to a few hundred metres.
The Novus range of programmable temperature transmitters bridges the gap between programmable and analog versions and is priced to compete with analog transmitters at a fraction of what programmable transmitters used to cost.
The PC programmable TxBlock and TxRail family is already, and consists of head and DIN rail mount transmitters. One single model can be configured to accept all thermocouple types and Pt100 RTDs. These transmitters are available with a 0-10 V or a 4-20 mA output and can be loop powered or powered by an external power supply of between 18 V and 30 V. Therefore, only one model is needed for various temperature applications greatly simplifying spares holding for users.
Both the headmount and DINrail versions are also available as isolated models. These transmitters are isolated between the sensor input and the transmitted current/voltage, which prevents interaction between multiple sensors linked to a common system (eg, PLC). Thus, damage is greatly reduced when a fault occurs, as one circuit does not interfere with another.
For more information contact Willem Krige, UniTemp, 021 762 8995, [email protected], www.unitemp.co.za
Further reading:
New temperature transmitters with Profibus connectivity
Temperature Measurement
Siemens is enhancing its temperature measuring device portfolio with the transmitter duo, Sitrans TH420 PA and Sitrans TF420 PA. Both devices feature Profibus connectivity, advanced safety functions and expedited commissioning all in one unit.
Read more...
Enhancing industrial efficiency through advanced temperature control
Iritron
Temperature Measurement
Iritron has been offering modular smart thyristor drives to the local and international mining, minerals and metals market, including the latest new leading innovations in temperature control technology. These drives combined with advanced proportional-integral-derivative (PID) control will change the way large industries manage their heating processes, reducing costs and extending equipment lifespan.
Read more...
Non-contact infrared thermometer
Temperature Measurement
AMETEK LAND has developed a new non-contact infrared thermometer for precise measurement and control during deposition processes in optical fibre manufacturing.
Read more...
High-precision fill quantity control in food supplement production
Temperature Measurement
Vital Products was looking for a precise and efficient solution to check the weight and ensure the completeness of its products. Minebea Intec, a specialist in industrial weighing and inspection technologies, was able to provide a solution.
Read more...
The critical role of temperature measurement in flame hardening
Instrotech
Temperature Measurement
Flame hardening is a heat treatment process widely used on parts made from mild steels, alloy steels, medium carbon steels and cast iron. Accurate temperature measurement is not just important, but critical for the success of flame hardening.
Read more...
Noncontact infrared temperature control in aluminium rolling process
Instrotech
Temperature Measurement
The aluminium rolling process is critical to the aluminium manufacturing industry, where precise temperature measurement is essential for ensuring high-quality product output and protecting equipment. The Optris long-wavelength camera can accurately measure strip temperatures in cold rolling and coiling applications.
Read more...
Where simplicity meets reliability
Endress+Hauser South Africa
Temperature Measurement
The new iTEMP TMT31 temperature transmitter from Endress+Hauser combines simplified selection, ordering, installation and operation with the highest reliability and long-term stability in one product.
Read more...
Automating car window defrosters
Temperature Measurement
Window defrosters are vital features in vehicles, particularly in colder climates. The automotive manufacturer seeks an efficient solution to quickly and precisely measure the temperature of the windows, ensuring that the connections, installed cables and wires work correctly and have no defects before the vehicle’s final release.
Read more...
The impact of thermal imaging in steam methane reformers
Temperature Measurement
As global demand for hydrogen, ammonia and fertilisers increases, LAND is empowering steam methane reformer operators to unlock efficiency gains at existing plants to meet ambitious production targets while also safely decarbonising.
Read more...
Proven indicators monitored in three dimensions
ifm - South Africa
Temperature Measurement
The VVB30x continuously detects vibrations in three measurement axes and uses them to calculate proven indicators for evaluating machine condition.
Read more...
printer friendly version