R7426A,B,C TEMPERATURE CONTROLLER WITH AND WITHOUT REAL TIME CLOCK
Summer / Winter Time Change
AddHour / SubHour (C.16 / C.17)
Default Programming DefProg (C.23)
Setting the control parameter DefProg to 1 resets all control
and configuration parameters to defaults (see Table 4 and
Table 5). Default programming is indicated by a display of def.
These configuration parameters are only available on
controllers with RTC. The configuration parameter AddHour
or SubHour are required to adjust the month for
summer/winter time change or vice versa.
After default programming, the parameter DefProg is reset to
The actual clock is incremented by one hour at 2:00 on the
last sunday of the month for winter/summer time change
PARAMETER SETTINGS AND
AddHour). The actual clock is decremented by one hour at
:00 on the last sunday of the month for summer/ winter time
Main Setpoint W1 (P.01)
The main setpoint is either set by the control parameter W1 or
by the external setpoint potentiometer if the configuration
parameter CPATYP = 3, 5 or 6.
Prestart Gradients PSTG_H / PSTG_C
(C.18 / C.19)
The configuration parameter PSTG_H or PSTG_C are
necessary for the optimum start program on controllers with
RTC. For heating and cooling applications, these parameters
determine the prestart gradient to reach the comfort setpoint
at occupancy start.
High/Low Limit Setpoint Wlim (P.02)
For high or low limit control, the control parameter Wlim is
used as setpoint.
During limit control, the throttling range Xp2 and reset time
tr2 are active.
If the comfort setpoint will be reached earlier or later than
expected, the controller corrects the prestart gradient by self-
adaption routine to optimize the start cycle.
Limit control will be active only if the T2 temperature signal
(control parameter T2ext = 0) is available or alternatively the
The optimum start cycle for heating or cooling can be
disabled by setting PSTG_H or PSTG_C to 0.
sensor T1 (control parameter T2ext = 1) is used also for limit
For cascade control, the limit setpoint Wlim determines the
control point at which the submaster setpoint (Wcas) maintains
the limit value and is not shifted anymore by the master
Optimum Start Self Adaption Speed
Adapt (C.21: Controller with RTC only)
This parameter is used by the self-adaption routine to
optimize the energy consumption during the start cycle. For
this optimization, a corrected prestart gradient is calculated
once per day. The adaption to the actual prestart gradient for
the next optimum start cycle is determined by the self
adaption speed Adapt (0% = adaption disabled and 100% =
max. adaption speed).
High or low limit control is in accordance with the con-
figuration parameter LimTyp (C.13).
Submaster Setpoint W (P.06)
The R7426A,B,C controllers provide cascade control which
uses two control loops, master and submaster to maintain the
master setpoint CTRP1. Cascade control will be active if
temperature sensor T2 is connected and the control para-
meter Wcas is set to any value other than OFF.
Damper Prestart Time tvd
This adjustment sets the control point of the submaster
control loop, discharge temperature (T2), at zero room
temperature deviation. If the room temperature deviates, the
submaster setpoint Wcas is automatically altered.
C.20: Controller with RTC only)
The damper prestart time tvd is active with the optimum start
program only and is used to set the time before occupancy
start (scheduled comfort mode) at which the output signal Y1
Cascade control is disabled if the submaster setpoint Wcas is
set to OFF.
(damper) switches to normal operation to supply fresh air to
the space in mixed air applications.
Low limit of CTRP2 is performed if control parameter
LimTyp = 0 and high limit of CTRP2 is performed if control
parameter LimTyp = 1.
Serial Communication Address Adr (C.22)
The configuration parameter Adr sets the serial
The serial communication bus allows the connection of the
PC-based Operator’s Terminal to one or several controllers. It
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.
Reset Span Adjustment R (P.07)
The reset span adjustment Rcas determines the reset effect in
Kelvin. The submaster setpoint Wcas is altered if the tem-
perature (T1) deviates by 50% of the throttling range Xp1.
Throttling Range Xp1 / Xp2 (P.08 / P09)
Proportional band (throttling range X ) adjustment determines
the temperature change, required at the main sensor (T1) and