For the fuel change without load dropping, the following special features must be taken into consideration:

1. A burner capacity of 0 MW generally corresponds to the load position of 0 digit for a fuel change without load dropping.

2. The burner capacity must be divided proportionally to the load position (e.g. 0.0 to 18.0 MW = 0 to 1800 digit).

3. The first load point must be assigned the low load (e.g. 1.0 MW = 100 digit) and the corresponding fuel must be adjusted to the corresponding load.

4. To permit the compound control system to calculate the required burner capacities from the load position, identical load positions must be used in each operation mode for the same burner capacities.

5. Minimum running time of compound control should be adjusted to the slowest fuel actuator since the minimum running time is used for the mutual control of fuels during a changeover. This has a positive influence on the uniform control of the fuels relative to each other.

6. The channels of the fuel actuators must be parameterized with fuel-related channel functions:

   Warning! Danger to persons!

   Channel functions 3 and 5 must not be used for fuel channels if the fuel change between the fuels is parameterized without load dropping or simultaneous firing! Then the channel functions 8, 9 and 10 must be used for fuels 1, 2 and 3.

   • Channel function 8 for fuel channel for fuel 1 example: Oil control valve or gas control damper fuel 1 only.

   • Channel function 9 for fuel channel for fuel 2 example: Oil control valve or gas control damper fuel 2 only.

   • Channel function 10 for fuel channel for fuel 3 example: Oil control valve or gas control damper fuel 3 only.

   • Channel function 11 for fuel channel for liquid fuels example: Primary air control damper of rotary cup atomizer or atomizing steam control valve of the steam pressure atomizer.

   • Channel function 12 for fuel channel for gaseous fuels example: Option.

7. The safety interlock circuits of the individual fuels must be available on the FSC independently of each other. They must both be able to be active simultaneously (no interlock).

8. The fuel actuators must be controlled via separate channels; no shared use of the actuators as in the mechanical compound.

9. The capacity ranges for connection/disconnection of the fuels with flame stability must be adjusted with the parameters "Load position MIN start secondary fuel" and "Load position MAX start secondary fuel".