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Date: 8-4-2010
Revision: 0
Form: 2396
following sources of demand. All sources that
are currently calling for heat will be true (multiple
items may be true at the same time) except
when WWSD is active, then CH demand is
inhibited.
CH Demand
CH Frost demand – true if any slave is calling for
CH frost protection and Frost protection
enable is true.
4.7.4 MASTER ACTIVE SERVICE
Is a data item which contains the identity of a
single source of demand that the LL Master is
currently serving according to its priority:
• None – no active service, LL master is idle
• CH
• Frost – burner demand is true for frost
protection
• WWSD – no high priority demand is active, and
WWSD is inhibiting CH demand (if any).
MASTER SERVICE STATUS
Is a data item used by pump control logic that
combines the Master Heat Demand and Master
Active Service data. It is implemented as
described by the Pump Control Block diagram.
Outdoor Temperature
For a Sola that hosts a LL master, the outdoor
temperature may be known from either of two
sources. If the host Sola has an outdoor sensor
that is reporting a valid temperature then this
sensor reading is used. Otherwise, if any slave
Sola is reporting a valid temperature as part of
its Data Poll message, then this temperature is
used.
The resulting outdoor temperature provides all
outdoor temperature needs for both stand-alone
and LL master purposes. If neither source has a
valid temperature then the outdoor temperature
is simply invalid and unknown, and the functions
which need this information handle it accordingly
per their individual definitions.
Modulation
Each demand source has one or more setpoints
that may be active and an operation sensor.
These are used to detect turn-on and turn-off
conditions. The difference between operating
point and setpoint determines the LL master's
firing rate
4.7.5 MODULATION SENSOR
LL MODULATION SENSOR: S5
The LL master's modulation sensor uses the S5
sensor (connector J8 terminal 11 and 12). If the
LL master is enabled and its sensor is faulty
then an alert will be issued.
LL MODULATION BACKUP SENSOR:
DISABLE, LEAD OUTLET, SLAVE OUTLET
AVERAGE
If the sensor chosen by the LL Modulation
sensor is faulty then the backup sensor
provided here may be used.
If Disable is selected then no backup will be
used.
If Lead Outlet is selected then the outlet
temperature of the lead boiler will be used as the
backup during firing.
If Slave Outlet Average is selected then
average of the outlet temperatures of all slave
boilers that are firing will be used as a backup.
When the burner demand is off and no burners
are firing then, for either Lead Outlet or Slave
Outlet Average, the lead boiler's outlet
temperature is used to monitor for burner
demand.
Setpoints
LL CH SETPOINT SOURCE: LOCAL, S2 4-
20MA
If the setpoint source is Local then the Sola
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
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