Monday 14 December 2009

Digital controllers

Entry-level models series of digital indicating controllers

Yokogawa Electric Corporation announces the release of the UT35A (quarter DIN size) and the UT32A (one-eighth DIN size), two entry-level models in the UTAdvanced™ series of digital indicating controllers.

These new low-cost models, which replace their UT300 range, have a sequence control function that is based on the general-purpose ladder logic programming language, and are targeted for use in the single-loop control of production equipment.

The UTAdvanced Series adopts an open system architecture with an Ethernet communications interface. They are compatible with MODBUS/TCP protocol and also (as an option) with the PROFIBUS DP protocol. In addition to eliminating the need for dedicated communication programs and converters for connecting to devices such as data-acquisition units and/or PLCs, this feature makes it easy to develop optimal multi-vendor systems for users.

Development background
Indicating controllers are embedded in industrial furnaces and other relatively small-scale production line equipment and installations, and are used to measure, display and control various types of data including temperature, pressure and flow rate. In April 2009, Yokogawa launched the UTAdvanced series of digital indicating controllers, featuring sequence control based on the widely used ladder logic programming language.

The first models in this series, the UT55A and UT52A, have gained a solid reputation for their contributions in raising efficiency and lowering costs by integrating peripheral devices such as relays. These high-end, high-performance digital indicating controllers have a wealth of control function modes, with the most capable units able to perform full cascade control for controlling relatively complex installations such as continuous furnaces.

However, there is also a need in the market for general-purpose indicating controllers that have only the functionality needed for controlling single-loop production equipment. To meet this need, Yokogawa is releasing the UT35A and UT32A entry-level models. These new products are expected to further enhance Yokogawa's digital indicating controller business.

Product features
The new controllers offer an optimum combination of functionality and price. They have a fixed control scan period of 200 ms and 300 steps for ladder programming, compared with the three control scan periods and 500 steps in the high-end UT55A and UT52A models. However, this is more than adequate for the single-loop control of production line installations.

The UT35A and UT32A also have capabilities that to date have been found in only high-end controllers, including a ladder language based sequence control function; support of the Ethernet or RS485 interfaces and MODBUS or PROFIBUS-DP communication protocols; a colour LCD display; and operation guidance functions including navigation keys.

Also included is a user default function. Not only is it possible via a simple function to reset the unit to factory default settings: it is also possible for the user to define his own 'default profile' to which it is possible to return. This means that an engineer can always quickly revert to a known working setup profile - without starting again from scratch or having to load a configuration file from a PC.

Target markets
Main target markets for the new controllers are machining facilities in a wide variety of industries including electrical equipment, machinery, chemicals, foods, semiconductors and automotive manufacturing.

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