Fireye BurnerLogiX ZB110 Manual page 31

motor (or valve actuator) to drive towards its closed or low fire position. Similarly, a decrease in the
steam pressure (or water temperature) will increase the control output signal, causing the valves and
dampers to move toward their open or high fire position.
The value of the modulating range (MOD RNG) determines how the BurnerLogix responds to
changes in the measured variable (steam pressure or water temperature). A small modulating range
will cause the control to respond quickly to small changes in steam pressure or water temperature. A
small value of MOD RNG might result in the firing rate motor to cycle excessively and possibly
cause the burner to actually short cycle. A large value would reduce the cycling of the firing rate
motor, but may cause the system to be somewhat sluggish in response to a change in steam pressure
or water temperature. Matching the capacity of the boiler to load system demand are important con-
siderations in setting the MOD RNG setpoint. Care should be taken when selecting this variable.
The BurnerLogix control also provides PID control (Proportional + Integral+ Derivative) to improve
system response to varying load changes. Refer to "Proportional plus Integral plus Derivative con-
trol.
Maximum Modulating Firing Rate Position (MOD MAX)
The Maximum Modulating Firing Rate Position is a programmable setpoint which will clamp the 4-
20mA control signal to the Firing Rate Motor. This setpoint will also affect the cycling rate of the
boiler. This setpoint is programmed as a percentage, from 0% to 100%.
Manual Positioning of the Firing Rate Motor (MOD USE)
Although normal operation of the BurnerLogix system is to automatically control the modulating
motor based on programmed set points, MOD USE provides the user the option of manually posi-
tioning the modulating motor. Manual control of the modulating motor is normally used in lieu of
the standard manual / auto potentiometer found on older burner cabinets. At times it may be desir-
able to either limit the firing rate or base load one boiler in a multiple boiler environment.
The MOD USE setpoint has two selections: AUTO and MANUAL. The AUTO selection will have
the BurnerLogix modulate the firing rate motor based on system demand. The MANUAL selection
will allow the user to manually command the firing rate position. The current MOD USE state is
displayed on the ALL-INFO screen.
CAUTION: As long as the setpoint MOD USE is programmed MANUAL, the BurnerLogix
WILL NOT control the firing rate motor based on system demand, but will remain in man-
ual control indefinitely.
Modulate Motor Position (MOD POS)
Use this setpoint to manually position the modulator (firing rate) motor. The motor will move as
long while the NEXT or BACK key are depressed. Use the RESET/MDFY key to save the position.
MOD USE, MOD POS and MOD MAX setpoints are all located in the BOILER PARMS sub-
menu. MOD POS is displayed only if MOD USE is set to MAN.
To manually position the firing rate motor:
1.
While in STANDBY and with burner off, and from the ALL-INFO screen, pressing the MODE
key will move to the top of the BurnerLogix Main menu where L1-3 OPEN or L1-3 CLOSED is
displayed. Pressing MODE again will move the display to either MOD USE if in AUTO mode
or to MOD POS if in MAN mode. If changing to MAN mode, press the RESET/MDFY key and
the NEXT or BACK key to change to MAN and then the RESET/MDFY key to save the
change. Press the NEXT key to move to MOD POS and then the RESET/MDFY key to manu-
ally position the firing rate motor. When complete, press the RESET/MDFY key to save the
position. Pressing the MODE key will move the display to the top of the BurnerLogix Main
menu screen and then to the ALL-INFO screen.
2.
While in AUTO or main firing period, and from the ALL-INFO screen, pressing the MODE key
will move directly to either the MOD USE if in AUTO mode or to MOD POS if in MAN mode.
If changing to AUTO mode and at MOD POS screen, use the BACK key to move to MOD USE
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