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Date: 8-4-2010
Revision: 0
Form: 2396
that way until the 4- 20mA signal is stable again.
LL CH 20MA WATER TEMPERATURE:
TEMPERATURE OR NONE
CH 4MA WATER TEMPERATURE:
TEMPERATURE OR NONE
These provide 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.
LL CH SETPOINT: 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.
LL CH TOD SETPOINT: 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.
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 AND BOOST (BOOST IS
FUTURE)
The outdoor reset and boost functions for the LL
CH functions will be 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
• LL CH TOD Setpoint
• LL Outdoor reset enable: Disable, enable
• LL CH ODR minimum outdoor degrees or
None
• temperature:
• LL CH ODR maximum outdoor degrees or
None temperature:
• LL CH ODR low water temperature: degrees or
None
• LL CH ODR boost time: mm:ss or None
• LL CH ODR boost max setpoint: degrees or
None
• LL CH ODR boost step: degrees or None
• LL CH ODR boost recovery step time:mm:ss or
None
The outdoor reset function requires the outdoor
temperature. This temperature may be obtained
from either a local sensor or a LL slave as
described earlier. If the outdoor temperature is
invalid and unknown, then no outdoor reset
action occurs and an alert is issued indicating an
invalid outdoor temperature.
LL CH ODR MINIMUM WATER
TEMPERATURE: 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.
4.7.6 DEMAND AND RATE
On/Off Hysteresis Includes hysteresis shifting
at turn-on, turn-off
LL OFF HYSTERESIS: DEGREES OR NONE
LL ON HYSTERESIS: 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.
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 scalars and
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