Two-Stage Heating And Cooling - ABB i-bus KNX Product Manual

4.3.6 Two-stage heating
and cooling
© 2009 Busch-Jaeger Elektro GmbH – A Company of the ABB Group
T
21 °C
Wendepunkt
Tu Tn = 3 * Tu
Tu = Verzugszeit
Tn = Nachstellzeit
In specific instances such as when using underfloor heating, it may be
necessary to install a quick additional stage for the heat control in order
to warm up the room rapidly. When the room thermostat is pre-set to
"supplementary-stage heating enabled", it has a second heating system with
switching control (1-bit) or a "quasi-continuous" control, which is controlled
with the 1-byte values 0% and 100%.
The parameters "gap of additional stage" and "Hysteresis (one-sided)"
enable you to specify when the additional stage switches on and off.
For example, if the setpoint is 18 °C and the hysteresis 0.5 K (one-sided) for
the additional stage, the controller switches on at 18 °C and off at 18.5 °C.
The same settings as for the additional stage heating also apply for the
additional stage cooling, except that for cooling an additional cooling stage
is activated if an adjustable temperature is exceeded to cool the room faster.
Because some actuators close (open without power) at a 1-bit value of "1" or
a 1-byte value of "255" and open at "0", the direction of the control value can
be changed with "invert control value".
Sollwert
Istwert
t
92