FirstOpNet DCS system for Cold Rolling Mills with adaptive control

The DCS control system designed by First Control is based on modern control technology with self-tuning control to achieve maximal production performance. Experience from several installations shows that the self-tuning regulator reduces the thickness deviations by 50-75% compared to conventional

Control package includes the following functions

Self-tuning thickness FB control
Self-tuning feedforward control
Self-tuning mass flow control
Automatic AGC start-up
Thick end disturbance reduction

Adaptive control of hydraulics
Mill safety protection
Mill setup
Thickness gauge setup
Thickness profile measurement

FirstOpNet operator interface
OPC system communication
Production quality supervision
Rolling statistics
General automation

Production result in an old mill

The diagram shows the improvements in strip thickness using First Control’s self-tuning regulator in an old Sendzimir Mill at Outokumpu Stainless in Långshyttan Sweden.

Each point in the diagram shows the average standard deviation in strip thickness during one month of production.
The upgrading of the mill was done in steps during about 3 years. The improvment after each new self-tuning function is seen as jumps in the performance curve above. In the end, the strip accuracy achieved (0.0005 mm) was better than most new mills.
The large improvement in strip quality meant that the company could increase their sales and the owner invested in two completely new mills which are also controlled by First Control’s self-tuning regulators.

Production result in a new mill

The table shows the production results in a recent Mitsubushi-Hitachi mill at Outokumpu stainless in Långshyttan, Sweden

The table shows the average standard deviation (s) for all production during. The quality measures are computed from unfiltered data during the whole rolling, from start to stop of the pass.
The operator is free to select the control strategy in each pass:

Self-tuning FB and FF control
Self-tuning mass flow control with FF
Self-tuning FB without FF control
Self-tuning Massflow without FF control

Fore more information

Adaptive control in cold rolling

Downloads

Adaptive control in MicroController XC (pdf 186kB)

Improved AGC Control using adaptive technique in Cold Rolling Mill (pdf 616kB)