CleaverBrooks CFC-500 Operation, Service And Parts Manual page 206

CB FALCON
Setpoints
Parameter
LL CH Setpoint source
LL CH 20mA Water Temperature
CH 4mA Water Temperature
LL CH setpoint
LL CH TOD setpoint
LL CH ODR minimum water
temperature
TIME OF DAY
The Time of Day has one sources of control: a switch contact.
Closed TOD is an on condition; open, then TOD is off.
OUTDOOR RESET
The outdoor reset for the LL CH functions are implemented as
described for a stand-alone CH loop.
Each of the loops which implements outdoor reset and boost
has its own parameters. The parameters used by the LL
master are:
• LL setpoint
Parameter
LL off hysteresis
LL on hysteresis
LEAD LAG PID
The behavior of the Lead Lag PID function is identical to the
behavior of the stand-alone CH PID function. The same gain
750-265
Table 40. Setpoint Parameters.
Local, S2 4-20mA
If the setpoint source is Local then the Falcon control's local setpoint system is used.
This setting enables the normal use of the CH setpoint, CH TOD setpoint, and the CH
outdoor reset parameters and functions.
If the setpoint source is S2 4-20mA then the setpoint is determined by the 4-20mA input on
S2, and the two parameters described below. If the 4-20mA signal goes out of range or is
invalid, and this persists for a specified time, then the setpoint source reverts to "Local". In
this case once it has gone to "Local", it remains that way until the 4-20mA signal is stable
again.
Temperature or None
These provided the 20mA and 4mA temperatures for the interpolation curve. If either of these
have the None value, are invalid, are out of range, or are too close for interpolation, an alert is
issued and the setpoint reverts to "Local" when it is selected as 4-20mA.
Degrees or None
This setpoint is used when the time-of-day input is off. If the ODR function is inactive then the
setpoint is used as-is.
If the ODR function is active then this setpoint provides one coordinate for the outdoor reset
curve.
Degrees or None
This setpoint is used when the time-of-day input is on. If the ODR function is inactive then the
setpoint is used as-is.
If the ODR function is active then this setpoint provides one coordinate for the shifted
(because TOD is on) outdoor reset curve.
Degrees or None
This specifies the minimum outdoor reset setpoint for the LL master. If the outdoor reset
function calculates a temperature that is below the temperature specified here, then this
parameter's temperature will be used.
If this parameter is invalid or None then the outdoor reset function will be inhibited and will not
run: if it is enabled then an alert is issued.
Table 41. On/Off Hysteresis Parameters.
Degrees or None
The LL hysteresis values apply to all setpoint sources. The behavior of the hysteresis
function is identical to the behavior of the stand-alone CH hysteresis function, except:
• where stand-alone CH hysteresis uses the on/off status of a single burner, the LL
hysteresis uses the on/off status of all slave burners: this status is true if any slave burner
is on, and false only if all are off.
• where stand-alone CH hysteresis uses time of turn-on and turn-off of a single burner, the
LL hysteresis uses the turn-on of the first slave burners and the turn-off of the last slave
burner.
Comment
• LL CH TOD setpoint
• LL CH ODR minimum outdoor temperature: degrees or
None
• LL CH ODR maximum outdoor temperature: degrees or
None
• LL CH ODR low water temperature: degrees or None
Demand and Rate
ON/OFF HYSTERESIS
Includes hysteresis shifting at turn-on, turn-off.
Comment
scalers and algorithms are used.
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