Operation Manual

Continuous valve actuator CHEOPS control
theben
As of: Jul-11 (Subject to change without notice) Page 58 of 71
5.7 Determine the maximum actuating value
5.7.1 Application
If within a system all valve actuators are only slightly open, e.g. one at 5%, one at 12%,
another at 7% etc., the heating boiler can reduce its output because only a small amount of
heating energy is required.
In order to guarantee this, the heating boiler requires the following information:
How high is the actuating value in the room, which currently exhibits the greatest heat
requirement?
With Cheops valve actuators, this task is handled by the "Maximum position" function.
5.7.2 Principle
The actuating values are constantly compared between all participants (Cheops valve
actuators). Those participant with a higher actuating value than the one received may send it,
those with a smaller one may not.
In order to accelerate the process, the greater the difference between its own and the received
actuating value, the greater the speed at which the valve actuator sends.
Thus, the valve actuator with the highest actuating value sends first and beats the remainders.
5.7.3 Practice
The actuating value comparison takes place via Object 3 ("Maximum position") where
for each valve actuator, a common group address for the maximum position is placed on
Object 3.
In order to start the actuating value comparison between the participants, one (and only one)
participant must send a value to this group address cyclically.
This task can be handled by either boiler or valve actuator.
If it is the boiler, it must send the smallest possible value, i.e. 0%.
If it is a Cheops valve actuator, the parameter " Transmission of object
"Max. actuating value"(for boiler control)" on parameter page " Security and forced mode”
must be set to any cycle time.
This valve actuator then regularly sends its own actuating value and the others can respond
accordingly.
Irrespective of which participants act as initiator, the "Transm. of object “max. actuating
value” (for heating system)" must be set to the default value for all other valve actuators, see
Figure: