ABB i-bus KNX, Руководство по эксплуатации продукта, Страница: 101 / 264

ABB i-bus
®
KNX
Commissioning
FCA/S 1.x.x.1 | 2CDC508134D0202 99
Valve is
Options: Heating valve
Cooling valve
This parameter determines whether the valve is defined as a heating valve or cooling valve.
Note
In the option 2 control values/2 valves (with or without switching object), one valve must be
parameterized as a heating valve and the other as a cooling valve, according to the installation
conditions.
Control value is received as
Options: Byte
Bit
This parameter defines how the sent control value is received by the room thermostat. Depending
on the selection, the communication object for the
Control value , p. 211, (1-bit or 1-byte) is
displayed.

1-bit: The control value is sent by the room thermostat as a PWM signal or a two-step signal
(ON/OFF). The parameter for setting the PWM cycle time is displayed (PWM = pulse width
modulation).
The following message appears:
Set cycle time PWM, open/closing time
for contr. value of valve drive in %
At recovery, controller fault,
forced oper. and characteristic curve

Note
Note
Pulse width modulation
With pulse width modulation, the valve is operated as with 2-point control exclusively in the positions
fully opened and fully closed . In contrast to a 2-point control, the position is not controlled via limit
values, but rather by the calculated control value, similar to continuous control.
The control value is fixed for a timed cycle and recalculated for the switch on duration of the output. The
control value 20 % at a cycle time of 15 minutes, for example, will be recalculated for a switch on
duration of three minutes.
The control value 50 % results in a switch on duration of 7.5 minutes.
Using pulse width modulation, a relatively exact control of the temperature is achieved without high
levels of overshoot. Simple thermoelectric valve drives can be used.