Honeywell HC900 - Figure 13 AMB Function Block Example

Function Blocks
AMB Auto/Manual Bias Function Block
70 HC900 Hybrid Control Designer Function Block Reference Guide Revision 11
2/07
Example
HFigure 13 shows an function block diagram using an AMB function block.
PT
MAIN STEAM
HEADER PRESSURE
PLANT MASTER
PRESSURE
CONTROLLER (PID)
OUT
-5 TO 105
TO AIR/FUEL
CONTROL (SP)
TO AIR/FUEL
CONTROL (SP)
OUT
-5 TO 105
OUT
-5 TO 105
IN
BOILER 1
SUBMASTER
BOILER 2
SUBMASTER
IN
BOILER X
AMB Block (Boiler Submaster):
Operators place AMB Block to “MAN” mode to adjust fuel setpoints up or down independent of each
boiler.
AMB: OUT = IN + BIAS
MAN MODE Bias is automatically calculated as operator increment or
decrement out value. Bias = OUT – IN
AUTO MODE Bias is a fixed value from the man mode calculation. Above
OUT = IN + Bias
Figure 13 AMB function block example