SIEMENS SIMATIC S7 + WINCC
Combustion Control
Combustion Control
This mesh allows for accurate metering of fuel into the boiler furnace and the precise relationship to combustion air flow, providing optimal burning conditions and avoiding unwanted deposition of unburned fuel. The regulating principle is based on a control system that provides boiler pressure rise, air supply and bagasse feed. To decrease the pressure, the bagasse is removed and the air is removed. Control is performed by sensing the main line master vapor pressure through a pressure transmitter (PT300), which sends a signal to the controller. The output signal from the controller acts directly on the fuel / air flows required for combustion by controlling the bagasse feeder (MT301 to MT304) and forced air fan (MT300) drives.
• Create the following variables in the symbol table:
| Name | Address | Type | Description | S7_m_c |
|---|---|---|---|---|
| MT300_RT | MD8 | Real | Forced Air Fan Ratio | True |
| MT301_RT | MD12 | Real | Bagasse Feeder nr.1 Ratio | True |
| MT302_RT | MD16 | Real | Bagasse Feeder nr.2 Ratio | True |
| MT303_RT | MD20 | Real | Bagasse Feeder nr.3 Ratio | True |
| MT304_RT | MD24 | Real | Bagasse Feeder nr.4 Ratio | True |
| MT300_VAM | M0.3 | Bool | A/M Speed Forced Air Fan | True |
| MT301_VAM | M0.4 | Bool | A/M Speed Bagasse Feeder nr. 1 | True |
| MT302_VAM | M0.5 | Bool | A/M Speed Bagasse Feeder nr. 2 | True |
| MT303_VAM | M0.6 | Bool | A/M Speed Bagasse Feeder nr. 3 | True |
| MT304_VAM | M0.7 | Bool | A/M Speed Bagasse Feeder nr. 4 | True |
• Create Function FC6 CTR_PIC300. Right-click on the Blocks folder and select Insert New Object > Function menu item.
• Open CTR_PIC300 and insert FB_PID function block.
| PIC300 | FB_PID | DB55 |
• Force PID action. When the pressure of the superheated steam increases, the speeds of the frequency inverters of the Forced Air Fan and the Feeders must decrease (less air and less bagasse) to maintain the pressure in the indicated SP. When the pressure of the superheated steam decreases, the speeds of the inverters should increase (more air and more bagasse).
• Move the multiplication factor for converting PV and SP to 0 to 100% at the PID input.
• With the forced air fan speed control in automatic (MT300_VAM = 1), the MV output of the PID is multiplied by a ratio of 0 to 2 to allow the maintenance of the setpoint (MT300_RT = 1), an increase in value (MT300_RT > 1) or a decrease in value (MT300 < 1). The speed output for the inverter is limited to 100%.
• With the speed control of the Bagasse Feeder nr. 1 in automatic (MT301_VAM = 1), the MV output of the PID is multiplied by a ratio of 0 to 2 to allow the maintenance of the setpoint (MT301_RT = 1), an increase in value (MT301_RT > 1) or a decrease in value (MT301 < 1). The speed output for the inverter is limited to 100%. The same is done for the other bagasse feeders.
• Remove the movement of the 50% value of the speed setpoint input parameter in MT300MM, MT301MM, MT302MM, MT303MM and MT304MM.
• Make the call to function FC6 CTR_PIC300 in OB1.
• Select Operator Control and Monitoring for DB55 PIC300.
• Compile AS and OS.
• Create front for PID Boiler Master Pressure at Controle_Pressao.pdl.
C script to show the PW_PID picture window object in the current picture.
The Picture Name property of the PW_PID picture window receives the name of the picture PID.PDL.
The TagPrefix property of the PW_PID picture window is set to CALD/PIC300. This instruction adds the text “CALD/PIC300” at the beginning of all dynamizations of objects within the picture window.