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Everyday routine in control technology:
The plant is "ready to go", and during commissioning it turns out that: "The sensors have been installed in an unfavourable position - the delay times are much longer than expected - process does not line out using the classical PID optimization method - no short-term solution without enormous costs". For process loops up to the 3rd order, PMA's established automatic self-tuning procedures are unbeatable. Previously, loops with a ratio <10 between dead time and recovery time (Tg/Tu) were considered as difficult to control, and a ratio <3 as uncontrollable. These ratios, as well as dominant dead times, are also found with thermal processes, furnaces, casting plants, pressure and flow control loops, etc. The associated control problems cannot be solved with conventional proprietary algorithms or classical tuning methods derived from textbooks (Ziegler/Nichols or Chien/Hrones/Reswick). Consequently, tedious experiments with alternative control parameters were a guarantee for sleepless nights. Nowadays, however, a similar situation is mastered quickly by means of the new PMA Tune - also by persons without years of experience. Simply connect your laptop to the front interface of the PMA controller, get the process into a stable condition (manual operation), and start the self-tuning function. Starting with the loop identification phase through to the determination of optimum control parameters, the Oprogramowanie package ensures secure and reliable control: Without overshoot or hunting of the process variable . stable line-out at the setpoint. Time-consuming tests are no longer needed. The user gains valuable time to consider possible restructuring of the loop or modifications of the control concept, such as relocation of measurement sensors or the implementation of interlinked control loops (master/slave solutions) or the use of 'expert systems' such as model-based predictive control (MBPC). Save time, money - and nerves With PMA Tune, the personnel on site (e.g. the control engineer during commissioning or the plant operator) have a PC-based tool that determines precise control parameters in the shortest time for a wide range of control loop structures. The defined parameters ensure stable control, whereby loop variations are also tolerated. For the tuning procedure, it is irrelevant whether the loop is self-regulating or not, or if the controller output is two-point, three-point (heating/cooling), stepping (with or without position feedback) or continuous. The only condition is that the PMA controller has a front interface. The user simply makes a coarse selection of the bandwidth for the required control dynamics. Subsequently, the Oprogramowanie uses the connected controller to initiate a step response of the process, and then determines the ideal control parameters. Hereby, even slight drifting of the process variable has no effect on the tuning procedure. The new parameter settings are transferred to the controller at the push of a button - and the plant is really "ready to go". *) The procedure is not suitable for oscillating processes or processes with non-minimal phases. |
Więcej informacji : PHU WEGA Kasjopei 30A 80-299 Gdańsk Tel.: ++48-058-308-71-18 Fax: ++48-058 305-19-26
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