Gemu 1436 cPos - Submenu for setting positioner parameters; 13.3.2 Setting the positioner parameters; Setting the optional digital input parameters

35 / 66
1436 cPos
13.3.2 Settingthepositionerparameters
PosCtrl:
Provides parameters for the positioner.
Pos P:
Corresponds to the positioner’s KP amplication.
The optimum value is determined by the positioner during
initialisation.
Pos D:
Corresponds to the positioner’s D amplication.
Pos T:
Corresponds to the decay time for the positioner’s D
component.
MinPos:
Denes the lower position of the control range (serves as a
closing limit).
MaxPos:
Denes the upper position of the control range (serves as a
stroke limit).
0
80
60
40
20
100
100
80
60
40
20
Physical
stroke
x [%]
Unlimited stroke
Limited stroke
Setvaluew[%]
OpenTight and CloseTight:
Determines the close tight function areas (complete
pressurization or ventilation of the actuator).
With this function the valve can be moved into the seat using
the maximum possible actuator force.The close tight function
can be activated for one end or both end positions.
Example:
If the setting CloseTight 0.5 % and OpenTight 99.5 % is made,
the valve closes or opens fully according to the following
diagram.
The hysteresis is 1 %.
Setvaluew[%]
Strokex
[%]
100
0.5 1.5
98.5 99.5
0
If the control characteristic curve (W function chapter 13.4.2) is
changed to the values 1:25 or 1:50, the CloseTight value should
be set at >2.0 (if the characteristic curve is 1:50) or >4.0 (if the
characteristic curve is 1:25), in order to shut the valve fully.
13.3.3 Settingthedeadzone
DeadBand:
Denes the permissible deviation – dead zone between set
value and actual value.
Eects both the positioner and the process controller.
The height of the system deviation should always
correspond to the requirements of the valve and the
control circuit. It is recommended that you do not
set a value of < 1.0% since this could (especially
for actuators with discontinuous movement proles)
cause oscillating control characteristics. This could
put a great deal of stress on the internal pilot valves
and cause them to reach the end of their service
life more quickly.
Basically: the smaller the xed value, the higher the
wear and the shorter the service life. Therefore, the
value should be set only as accurate as needed.
13.3.4 Settingtheoptionaldigitalinputparameters
Digital Input:
Submenu for setting the digital inputs
In W:
Denes the functions of the High signal at digital input In
W (connection at set value input, only eective for manual
operation).
In X:
Denes the functions of the High signal at digital input In X
(connection at actual value input, only eective when operating
as a positioner)
In 1:
Denes the functions of the High signal at digital input 1
In 2:
Denes the functions of the High signal at digital input 2
Parameter Function
Function at
Low signal level
Function at
High signal level
OFF
Digital
inputs
deactivated
OFF/ON
Sets the
positioner
to the
pause
mode
OFF:
Positioner in
pause mode
ON:
Positioner active
Safe/ON
Moves the
positioner
into a safe
position
Safe:
Positioner moves
to the position
defined under
Error Action
ON:
Positioner active
ParmSetB0
Loads
parameter
sets into
working
memory
See following table
ParmSetB1
Loads
parameter
sets into
working
memory
Poti / Ix
Function of
the actual
value
output
Poti:
Valve position
Ix:
Process actual
value
Current signal for
ParmSetB1
Current signal for
ParmSetB0
Memory which is
read out
0 0 P1
0 1 P2
1 0 P3
1 1 P4