Basic Documentation

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Siemens Actuators SAX.., SAY.., SAV.., SAL.. for valves CE1P4040en
Smart Infrastructure Functions and control 2020-01-30
4.12 Forced control Z
Forced control is affected by changeover of acting direction. It uses the following
operating modes:
Z-mode
No function Fully open Fully closed
Overriding
positioning signal “Y“
by 0…1000 Ω
ConnectionsTransmission
Equal-percentage or
linear characteristic
Equal-percentage or
linear characteristic
Contact “Z“ not
connected,
valve follows
positioning signal ”Y”
Contact “Z“ is
connected directly to
“G“,
positiong signal ”Y” has
no impact
Contact “Z“ is
connected directly to
“G0“,
positiong signal ”Y”
has no impact
Contact “Z“ is
connected to “M“ via
resistor “R“,
starting point at 50 Ω,
end point at 900 Ω,
positioning signal ”Y”
has no impact
The operating modes "Z" shown are based on factory setting "direct acting" and a
"push to open" valve.
4.13 Communicating actuators Modbus RTU
4.13.1 Detection of valve seat
The actuators feature force-dependent valve seat detection. After calibration, the
exact valve stroke is filed in the actuator’s memory. When the actuator reaches the
respective end of stroke, it does not hit the valve’s seat at full speed, but stops for 5
seconds at about 1% before the stored position is reached. If the positioning signal
stays at 0% or 100%, the actuator travels to the calculated end position at reduced
positioning speed and builds up the required nominal force.
This function extends the actuator’s service life since the dynamic forces are
reduced when approaching the valve seat and there will be less strain on the gear
train.
In addition, the actuator’s oscillations in the case of instable control are
suppressed.
If no force is built up in the calculated end position (e.g. in the event of temperature
effects for instance), the actuator continues to operate at a reduced positioning
speed until the nominal positioning force is restored. This ensures that the valve
always fully closes.
SA..61.. only
Note