Continuous Controller - ABB i-bus KNX Product Manual

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4.3.2

Continuous controller

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100%

A continuous controller has a continuously changing control value, which

can take values between 0 and 100%. With the KNX the control value signal

is converted to a 1-byte value, i.e. the control value of 0% corresponds to

the value "0" and the control value 100% corresponds to the value "255".

Devices such as electromotor actuators can be controlled by a continuous

controller with a 1-byte control value. They convert the received value

directly to the valve position with an integrated motor. This enables optimum

control.

The 1-byte control value of a continuous controller can also be sent to KNX

heating actuators, which convert the 1-byte signal to a PWM value. This

can be used to control electrothermal valves. It may be useful to restrict

the dynamic range, because electrothermal valves required a certain time

to open and close (see also page 90, Section 4.3.3 PWM controller). This

is done with the parameters "minimum control value" and "maximum control

value". For example, if a maximum control value of 80% is preset, the

controller always automatically sends the value 255 if a control value of 204

is exceeded.

To prevent unnecessary bus loading the magnitude of the control value can

be set to enable it to be sent on the bus. The setting is a percentage value.

The transmission of the control value is determined by a cycle time if it has

not changed. The cycle time should be set too small (e.g. every 10 min).

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