Burner control units ensure the safe operation and monitoring of firing sequences for gas and oil burners in industrial thermoprocessing systems. For example, they offer variable safety times for opening the fuel valves, allow the pre-ventilation time to be adjusted for freely selectable blower outputs and boiler rooms and carry out a gas valve test (leak test) in accordance with EN 1643 with two main gas valve outputs. Their task is to reliably manage the subsequent safety functions in the monitoring sequence: pressure, temperature and flame monitoring, safe start-up, for example pre-purge and ignition, as well as shutdown, for example afterburning or shutdown, of the burner system. Safe monitoring of the emergency stop chain is also the task of a burner control unit. Other functions that are safely monitored are the fuel/air ratio, the activation of valves, dampers and actuators, the start-up and shut-down of valves and the high-temperature system. In addition, the automation also ensures secure data exchange and the visualization of operating states and diagnostic messages. A modern control system can supply all status and diagnostic data, which can be displayed and evaluated locally or remotely for other devices via fieldbuses or Industrial Ethernet.

Safety for boilers and co.

Burner management in the baked goods industry: The Austrian wafer baking machine manufacturer Bühler Haas uses the configurable small controller 'PNOZmulti 2 Burner': It takes over the 'functional safety' and 'burner control' tasks of the previously separate burner controllers in a single system.

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This monitoring sequence can be found in all Process Heat applications, regardless of whether they are single burners, burner groups or interlinked systems. One requirement always remains the same: the automation solution must solve the tasks of safety and automation technology as well as being convenient and easy to use. Manufacturers such as Pilz therefore offer systems that can be adapted to different applications in terms of their complexity and take into account the specific requirements of combustion technology in terms of hardware and software. In industrial gas and oil firing systems, for example, all functions along the gas control path, safety-relevant flame monitoring and all other system-related safety functions can be monitored, controlled and visualized.

Safety all-inclusive

In simple and less interlinked systems, small controllers take over the monitoring of safety in heating process applications. For example, the base unit 'PNOZ m B1 Burner' of the safe, configurable small controller 'PNOZmulti 2' from Pilz can be used as a safety controller to safely monitor and control not only the burner itself with its safety functions, but also the entire plant. Using predefined and certified function blocks, the monitoring can be adapted to different burner applications - for example pilot burner or non-guide burner, direct or indirect ignition, low or high temperature operation. The mini control unit also controls the safety valves of a burner in accordance with standards; an extension module has four safe, diverse relay outputs in accordance with EN 50156-1. Even complex safety applications can be implemented with this system, which has integrated diagnostics - one basic device monitors up to twelve burners.

However, small controllers reach their limits where long furnaces with dozens of burners are common - for example in the metal, glass and ceramics industries. In such plants, a large number of inputs and outputs are required, which are distributed over large spatial areas. Here, control systems such as 'PSSuniversal PLC' from the 'PSS 4000' automation system enable the safe management of all the burners present in an application. There are also complex, interlinked systems in which control systems with the appropriate software for burner management take over the safety of the system. For example, the integrated diagnostics can be used to display the status of the burner. As burners have to pass through various stages and sequences in accordance with the standard and have to meet certain conditions, the visualization must ensure that the operating personnel can read the status at a glance via a display or HMI. An additional graphical display of the flame parameters for all burners in a system and a display of the sensor data in the system display are part of the extended scope of diagnostics. Comprehensive diagnostics are particularly important for industrial systems that are distributed over a wide area, so that a quick response is possible if a fault occurs anywhere in the overall system.

Software modules for burners

The 'PNOZmulti Configurator' software tool for the small controller 'PNOZmulti 2' supports project planning, configuration creation, documentation and commissioning of safe combustion plants, including extensive diagnostics options.

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All safety functions relevant to burner management are available in approved and encapsulated modules via software. Only the available process signals and the input/output modules are decisive for how many monitoring and control functions can ultimately be used. The function modules can be used several times within the hardware limits and thus offer various options for optimizing the system - beyond the individual burner for a burner network or even the entire system.

The base unit 'Burner' of the small controller 'PNOZmulti 2', for example, supports a burner function block of the software tool 'PNOZmulti Configurator'; a maximum of twelve burner function blocks can be configured per base unit. This software element emulates the extended functionality of a flexibly configurable electronic burner control unit. It is available for configuring the base unit 'PNOZ m B1 Burner' and is certified in accordance with the relevant European standards, including EN 298 and EN 50156.

The software for control systems, such as 'PAS4000' in the automation system PSS 4000, can be characterized by hardware-independent programming. It can be used to configure function blocks that focus on specific application scenarios of a burner application. The 'Burner Management Software Package' can be used to implement programs for controlling different burner types and at the same time execute safety functions such as safety door contacts, emergency stops and light curtains. As the function blocks for burner management are prefabricated and TÜV-certified, they are easy to install and validate.