Technical description
„Aktor M ST L Modbus“
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101274584-V01.11.2019
The cycle time can be configured via the Modbus
parametrization.
If the value is zero, this function is deactivated.
3.2.2 Calculation functions
Calculation of the volume flow
In combination with a pressure independent control
valve “Cocon QTR/QFC”, the current volume flow is
calculated on the basis of the set valve characteristic
line and the current position of the actuator and can
be queried via Modbus.
Calculation of the thermal output
The current thermal output is calculated on the basis
of the calculated volume flow and the temperature
difference between the supply and return pipe and
can be queried via Modbus.
3.2.3 Limitation function
Return temperature limitation (register 315)
Return temperature limitation is carried out on the
basis of the limit value configured via Modbus and
the current measured return temperature. When ex-
ceeded or undercut, the volume flow will be reduced
until the limit value is reached again.
Limitation of the thermal output (register 314)
Limitation of the thermal output is carried out on the
basis of the limit value configured via Modbus and
the calculated current output. When exceeded, the
volume flow will be reduced until the limit value is
reached again.
3.2.4 Control function
Output control (registers 130, 200, 301, 310, 311, 410)
Control to a defined output value can be carried out
on the basis of the calculated current output.
Room temperature control (registers 131, 200, 300,
310, 311, 403)
Room temperature control is carried out on the basis
of the nominal temperature configured via Modbus
and the transmitted current room temperature.
Return temperature control (registers 130, 200, 302,
310, 311, 404, 405)
Return temperature control is carried out on the ba-
sis of the nominal temperature configured via Mod
-
bus and the current measured return temperature.
3.2.5 System monitoring
Leakage detection
A possible internal leakage is detected on the basis
of the measured flow and return temperature with the
valve closed.
A leakage is detected if the measured temperature
difference exceeds 8 K for at least 6 hours with the
valve closed.
Operating and fault messages
All data registered by the actuator can be queried
via Modbus. The state of the hydraulics can be
assessed on the basis of these data and possible
errors and failures can be detected at an early stage.
Bus monitoring
The bus failure detection can be parametrized via
Modbus (see section
