Honeywell R7426B - Page 17

R7426A,B,C TEMPERATURE CONTROLLER
17 63-2564—1
Prestart Gradient: PSTG_H / PSTG_C (C.18 / C.19)
These parameters determine the necessary prestart gradients
to reach the occupied setpoint at occupancy start. The
controller modifies the prestart gradient to optimize the start
cycle through a self-adaptation routine.
NOTE: Disable the optimum start cycle for heating and/or
cooling by setting PSTG_H or PSTG_C to 0.
Damper Prestart Time: tvd (C.20)
The parameter tvd is active with the optimum start program
only. It sets the time before occupied mode switches the
output signal O1 to supply fresh air to the space in mixed air
applications.
Optimum Start-Self Adaptation Speed: Adapt (C.21)
The self adaptation routine uses this parameter to optimize
energy consumption during the start cycle. A corrected
prestart gradient is calculated once per day. Adaptation to the
actual prestart gradient for the next optimum start cycle is
determined by the Adapt parameter:
• 0 percent disables adaptation.
• 100 percent utilizes the maximum adaptation speed.
Serial Communication Address: Adr (C.22)
The parameter Adr sets the serial communication address.
The serial communication bus allows to connect the
Operator’s Terminal to one or several controllers. This PC tool
provides access to all application configuration and control
parameters, time schedules, input and output values of the
connected controllers and easy setting of these via the bus by
mouse click or keyboard.
Default Programming: DefProg (C.23)
Setting parameter DefProg to 1 resets all parameters to
default values (see Tables 13 and 14). Default programming is
indicated by a display of def.
NOTE: After default programming, DefProg resets to 0.
TRAMP Time (C.28)
The parameter TRAMP determines the time in the start-up
routine during which the W1 setpoint decreases from its
temporary value to the normal programmed value.
NOTE: This only operates with an OAT sensor connected
and the OAT is below 42°F.
High/Low Limit Setpoint: W
lim
(P.02)
For high or low limit control, parameter W
lim
is the setpoint.
During limit control, the throttling range Xp2 and reset time tr2
are active. Limit control is active only when I02 temperature
signal (I02ext is 0) is available, or sensor I01 (I02ext is 1) is
used for limit control.
For cascade control, limit setpoint W
lim
determines the control
point at which:
• Submaster setpoint (W
cas
) maintains the limit value.
•W
lim
is not shifted by the master control loop.
NOTE: High or low limit control is in accordance with the
configuration parameter LimTyp (C.13).
Compensation Changeover Point: W
comp
(P.03)
The parameter W
comp
defines the start point of summer or
winter compensation.
Compensation is performed:
• Above W
comp
for summer compensation.
•Below W
comp
for winter compensation.
Summer/Winter Reset: Su/Wi (P.04/P.05)
Summer/Winter reset settings determine the compensation
sensor (I03) reset effect (TComp) on the main setpoint (W1).
To calculate winter and summer reset, throttling range must
be considered in proportional-only control (see Table 15). With
P+I control xp is 0.
NOTE: Compensation changeover (Xp) at +68°F OAT.
Table 15. Summer/Winter Reset Calculation.
Reset Span Adjustment: R
cas
(P.07)
The reset span adjustment (R
cas
) determines the reset effect
in degrees. If I01 deviates by 50 percent of the throttling range
(Xp1), this effect alters the submaster setpoint (W
cas
).
Throttling Range: Xp1/Xp2 (P.08/P09)
Throttling range (Xp) adjustment determines the change
required at the main sensor and limit or cascade sensor to
operate the output device through full stroke. Xp1 is the main
control loop throttling range. Xp2 is used when limitation or
cascade control (submaster control loop) are active (see
Table 16).
Control
Schedule
Room
Temperature (I01)
OAT
(I03/Tcomp)
Throttling
Range (XP)
Winter 68°F 68°F 4°F
72°F 5°F
%
Summer 68°F 68°F 4°F
79°F 95°F
%
AutWi
∆IO1 Xp+
∆OAT
---------------------------
x100
72 68–()4+
63
--------------------------------
x100 13≅==
AutSu
∆IO1 Xp–
∆OAT
---------------------------
x100
79 68–()4–
27
-------------------------------
x100 26≅==