Asco joucomatic POSIMATIC 606 Série Manuel D'installation page 17

INSTALLATION
A flow value can be assigned to every setpoint at distance intervals of 10%. These points create a polygon with 10 straight
lines resulting in an image of the characteristic curve of the valve.
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The setpoints can only be entered at 28. SETP FUNCTN = free.
41: X-DISPLAY
Standardisation of manipulated variable
Limiting the manipulated variable via 21: MIN POSITION (YA) and 22: MAX POSITION (YE) creates two different scales
for display and position feedback (POSITION or FLOW).
POSITION is the mechanical position (0 to 100%) between the hard stops of initialisation and is not influenced by YA or YE.
FLOW is the standardisation of the display (0 to 100%) to the range between YA and YE and to the characteristic curve of
the valve selected with 28: SETP FUNCTN. The setpoint (0 to 100%) is then related to this FLOW range (0 to 100%).
X-DISPLAY can be changed to refer the display and the position feedback (x) to the flow (also if characteristic curves of
valves are used).
In this case, YE, YA and the characteristic curve of the valve is taken into account.
42: DEADBAND
Dead zone of the positioner
The dead zone specifies the maximum allowable deviation between the feedback value and the setpoint.
If DEADBAND = auto, the dead zone is adjusted to the requirements of the control loop during initialisation. The fixed
preset value for the dead zone is used for all other discrete settings.
Jumpy or nervous movements of the valve may occur if the setting for DEADBAND is too small.
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Stroke x (%)
FREE (factory setting)
1:25 inverse
Fig. 10: Characteristic valve curves
POSIMATIC
Setpoint w (%)
1 7