Flexible controller aids in-plant standardisation

System Integration & Control Systems Design

Systems - process or technology specific suppliers

April 2002 System Integration & Control Systems Design

While small in size, its makers say that the Gefran 600 still performs up to scratch with the latest controller technology. The 600 can easily control any thermal process thanks to its robust control algorithms and its 0,2% accuracy.

It has an operator interface protected by a Lexan membrane that ensures an IP65 protection level, a double LED display with four digits, a 4-key keypad with one key configuration for manual/automatic, hold, alarm reset and changing between dual set points. Everything is designed to simplify use. All system information from process variables, set points, state of in and outs and error messages are displayed. The instrument requires few software parameters, which means that the controller can be used immediately after setting the set points and any alarm limits. The automatic tuning function is simple and can be launched from the front keypad.

For people requiring simplified programming, Gefran offers a PC configuration kit for Windows, which configures the instrument in seconds, saves programmes, prints data, displays trends and prints historical data, in addition to recovering factory setting functions. Constant diagnosis of the control loop prevents breakdowns and the 600 will notify the user in the event of a problem. The user can decide the state of alarm outputs or a power level to supply in case of a breakdown. A protection code permits authorised users to block access to the configuration parameters once instrument set-up is performed to prevent operator error or the unauthorised changing of parameters.

The double set point, timer and set gradient functions are suitable for a wide range of applications. About 60 different input types are pre-programmed, including thermocouples, thermoresistors, PTC, 0-60 V, 0-1 V, 0-5 V, 0-10 V and 4-20 mA. For special nonlinear sensors customised values can now be entered in 32 segments. The type of input is selected from the faceplate keys, so no external shunts are required. An auxiliary CT 50 mA is available for load control. Up to four outputs can be chosen, including relays, logic, triac, 4-20 mA analog or 0-10 V, all freely configurable. Another isolated output is available to power external transmitters. The optional digital input allows switching between two set points, alarm reset and manual or automatic switching. The serial dialogue option, available in standard RS485, allows connection to supervision systems, PLCs, or simple terminals by means of two available protocols: Cencal and Modbus RTU.

Summary of noteworthy features:

* Lower in cost than previous models.

* Enhanced control capability for complicated and difficult processes.

* Dual set point for standby operation.

* Logical and easy set-up procedure.

* Three alarms with a completely configurable function.

* Multiple failsafe features.

* Hot/cold function with a selection of cooling fluid.

Neil Coetzer, UniTemp:

011 392 5989

Dieter Butow

021 762 8995

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System Integration & Control Systems Design

Flexible controller aids in-plant standardisation

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