
APV_CU4 AS-i_UK-5_072018.indd
UK
Control Unit
CU4 AS-interface
Instruction manual: UK - rev. 5
APV
8
3. General Terms
3.3.
Function of the individual components
The installation of the control unit is undertaken by special adapters
which are available for the different valves types, see chapter
5. Adapter. The snap connectors for supply air and pneumatic air
to the individual cylinders at the valves are located at the outside of
the control unit. In case of the control units for valves with turning
actuator, the pneumatic air is transferred internally to the actuator.
The air supply of the control unit is equipped with an exchangeable
air filter. Observe the required compressed air quality! Please also
see chapter 4.5.
The number of the solenoid valves installed in the CU4 depends on
the valve actuators to be controlled. Single seat and butterfly valves
and double seat valves without seat lift function require 1 solenoid
valve. Control units for double seat valves are equipped with
3 solenoid valves. For the manual actuation, the solenoid valves are
provided with a safe lever which is easy to operate.
The electronic module installed in the control unit fulfills the task to
process the electric signals from the control, to control the solenoid
valves and to evaluate the feedback signals from the feedback unit.
Moreover, the signalling and indication of the valve positions as well
as additional diagnostic functions are undertaken via the electronic
module.
The electronic module is the interface between control actuators
or sensors. Depending on the control type, different modules
are available, e.g. Direct Connect, AS-interface, Profibus and
DeviceNet.
A feedback unit is required to detect the valve position. The CU4
AS-interface is equipped with 2 adjustable Hall effect sensors.
These are activated by a valve control rod installed at the operating
cam. In this way, the
open
and
closed
valve position can be
detected.
The 2 Hall effect sensors are continuously adjustable over an
additional range. Thus, feedback messages for different valves with
different stroke lengths can be adjusted properly. As an alternative,
external proximity switches can be connected instead of the
integrated Hall effect sensors when the valve position indication is
undertaken direct at the process valve.