Fireye BurnerLogiX BLL510, Руководство пользователя

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FIGURE 9.
SEQUENCE OF OPERATION - MODULATING CONTROL
Note: Refer to Figure 10.
The BurnerLogix also performs the modulating control function of the firing rate motor based on
system demand. The position of the firing rate motor will operate according to the following set-
points:
STM STPT
1
(Steam Pressure Setpoint) - This determines the steam pressure the BurnerLogix will
maintain the boiler. When the steam pressure is at this setpoint value, the firing rate motor is at the
low fire position (0%).
or
WTR STPT
1
(Water Temperature Setpoint) - This determines the water temperature the Burner-
Logix will maintain the boiler. When the water pressure is at this setpoint value, the firing rate motor
is at the low fire position (0%).
MOD RNG (Modulating Range) - This determines the range of steam pressure (or water tempera-
ture) in which the firing rate motor is commanded from its low fire (0%) to its high fire position
(100%). This is a differential value that is
subtracted from the steam pressure setpoint ( STM STPT )
or water temperature setpoint ( WTR STPT ).
MOD MAX (Maximum Modulating Firing Rate Position) - This restricts the 4-20mA control signal
to the firing rate motor.
Note: The modulating range setpoint (MOD RNG) is a differential value. Point “C” (Steam pressure
or water temperature in which the firing rate motor is at the high fire position) is determined by sub-
tracting the programmed value of the modulating range (MOD RNG) from the Steam Pressure Set-
point (STM STPT) or Water Temperature Setpoint (WTR STPT).
If the steam pressure (or water temperature) is:
— Between Points D and E, the firing rate motor is in the low fire position.
— Between points C and D, the firing rate motor position is determined by the slope of the line
C-D. The slope of this line is determined by the value programmed for the setpoint MOD
RNG .
— Lower than Point C, the firing rate motor is in the high fire position (100% or value deter-
mined by MOD MAX ).
Whenever the steam pressure (or water temperature) is within the Modulating Range, an increase in
pressure (or temperature) value will reduce the control signal to the firing rate motor, causing the
LOW
FIRE
D E
STEAM PRESSURE (PSIG)
11 12 13 14 15 16 17
MOD
MAX
C HIGH
FIRE
100%
20mA
MOD
MAX
(e.g.: 80%)
0%
4mA
MOD RNGE = 3 PSIG
STM SP = 15 CUT OUT = 2
CUT IN = 0
OPERATING CONTROL
OPENS AT 17 PSIG AND
CLOSES AT 15 PSIG
FIRING RATE
POSITION
BOILER
FIRING
RATE MOTOR