750-382
CBT
4-27
Falcon control functions and customer interface
4.5 — Falcon control functions and customer interface
Following is a brief overview of the Falcon control features on steam boilers. Please refer to the Falcon Control
operating instructions in Appendix A for more detailed explanations.
• Set Point
• Time-of-Day (TOD) Set Point
• Hysteresis On and Hysteresis Off
• PID modulation control
• Remote Enable and Remote 4-20mA Input
• Remote Modulation
• Remote Set Point
• Configurable pump/auxiliary relay contacts
• Annunciator
• Diagnostics
• Lockout/Alarm History
• Trend Analysis
• Modbus communications
Set point, TOD set point, hysteresis on, hysteresis off, and PID load control
The set point is the value that the boiler’s PID load control attempts to maintain in order to meet the steam
demand. The modulating set point can be adjusted at the Operation page or under the Steam Configuration
parameter group. No password is required to change the set point. To change the set point at the Operation
page, press the set point value next to “Normal”. Clear the current value and enter the new value. Press <OK>
to establish the new set point.
The Time-of-Day (TOD), or setback, set point is an alternative set point that is enabled when a remote contact
connected to terminals J10-2 & J10-3 is closed (Refer to Figure 2-8 CBT Wiring Diagram). When the circuit is
open, the boiler control reverts back to the normal set point. The TOD set point can be adjusted at either the
Operation page or under the Steam Configuration parameter group. Service level password login is required to
change this parameter.
The hysteresis on and hysteresis off points can only be changed under the Steam Configuration parameter group
and require a login with the Service level password. Hysteresis on is the differential below the current set point
at which the boiler will restart following an off cycle. Hysteresis off is the differential above the current set point
at which the boiler will cycle off – effectively the boiler’s operating limit. These two parameters apply to both
the normal and TOD set points. To minimize the frequency of cycling the boiler on and off, the values of either,
or both, of these settings may be increased. Default settings for Hysteresis on and off are 0 and 3 psi,
respectively.
The PID (Proportional-Integral-Derivative) load control operates to generate the demand source’s modulation
rate. Under Steam configuration, the PID gain values can be adjusted to match the desired modulation
response. The default gain value settings of P=50, I=50 & D=0 have proven to work well with typical steam
boiler applications.
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