For the purpose of maintaining the water level in the steam boilers in Šećerana Crvenka, PLC Siemens S7-1200 was used as the executive element, while monitoring and management is carried out via the Weintek 10″ touch terminal, i.e. the Wonderware Scada application. The level in each boiler is controlled using two sensors. , whose values are averaged by the software. If there are incorrect measurements of one of the sensors,
the automation system recognizes this and excludes the given sensor from the calculation, and takes only the second sensor into account.
Due to sudden and frequent changes in steam consumption during production, automatic maintenance of the water level in the boilers based only on the currently measured level was not possible. For this reason, a three-component PID has been implemented for level maintenance, which uses the current water level, water flow for filling the tank and steam flow at the boiler outlet as input parameters.
If necessary, steam pressure is also monitored in automatic mode, which additionally regulates or corrects the three-component PID.
