The boiler control continues to play a decisive role in ensuring safe, reliable and economic operation.
The safety requirements of the various regulations for installation and safe operation of boiler systems must therefore be observed. However, in addition to safety and reliable operation, further energy management requirements, such as data logging and continuous optimisation of boiler operation, are just as important. Furthermore, all the options for managing production from a central automation system should be available as operation. Overall economic performance is only possible through internal communication between the steam consumers and steam generators.
The basic tasks of the control cabinet are:
- Safety functions
- Control functions
- Operation and fault messages
- Data logging and evaluation
- Control interface
- Third-party maintenance
Since 2001, Bosch Industriekessel GmbH has been the first boiler manufacturer to use PLC-based control systems as standard in shell boilers. The concept became a resounding success on the market and has in the meantime become standard equipment.
The control systems are continuously under further development. A high degree of operating data transparency and connectivity is achieved using touchscreen displays with intuitively-operated graphical user interface in combination with the programmable logic controllers.
In addition to controlling the boiler, a number of additional control tasks must also be performed in a boiler system. These are dealt with together with the networking of controls in the chapter System control.
Nowadays, hardware from the field of programmable logic controllers which has been tried-and-tested in industrial applications is used more or less everywhere in state-of-the-art control systems to carry out the necessary control tasks at the boiler and in the boiler house.
The devices perform all control functions of the boiler or boiler system and can communicate with other controls (e.g. burner management systems, separate controls of boiler house modules and higher-level process control systems) via bus systems or networks. Due to the very high demands in terms of reliability, the safety chain is normally implemented using conventional contactor and relay technology.
All control software is stored on a micro memory card. This dispenses with the need to use back-up batteries or EPROMs to safeguard against voltage failures. The devices are compact, modular and are screwed onto a profile rail to form a robust EMC-compliant assembly. Depending on the requirements, optional devices such as additional inputs and outputs or a communication processor, e.g. for Profibus DP, can be combined for interfacing with the central automation system. Additional options are available such as an Industrial Ethernet network for connection of several control modules or preparation for the remote access MEC Remote.
The complex and stringent demands for safe boiler operation are met using factory-tested software function modules which are specially tailored to the relevant boiler and boiler system controls. The customer benefits from systems with a wide range of variants in which the individual software modules have already been used and tested many times over in practice. Special individual programming is only occasionally carried out in exceptional cases.