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Selection of the preset value with comparison of
target/actual value
Clamping pressure monitoring with variable tolerance range
As in the preceding example; with the following conditions:
• Preset values 0 ... 315 bar; control voltage 0 ... 10 V; basic tolerance
= ± 1 bar; hysteresis error of the proportional valve +11 bar/-8 bar.
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ENGLISH
LS1 = 11
1
315
1
0
315
P2[bar]
P1[bar]
-1
2
3
LS2 = -8
1: selection of the preset value (0 ... 315 bar)
2: shifting SP1; above the line output 1 is switched.
3: shifting SP2; below the line output 2 is switched.
Display: Dmod = P1: applied pressure / actual value is displayed.
Dmod = P2: valve pressure / preset value is displayed.
Dmod = P1-2: difference between preset value and actual value is displayed.
SP1 = 1
OU1 = Hno
Output 1 is to switch (= ON) when the valve pressure is more
than 1 bar above the preset pressure.
InP2 = U
The plc controls the valve pressure by a voltage signal.
ILP2 = 0
IHP2 = 10
The voltage range for the valve control is between 0 and 10 V.
IEP2 = 315 The plc changes the preset value from 0 to 315bar (max. pressure).
LS1 = 11
Until the maximum pressure has been reached, the tolerance
range changes by + 11 bar in a linear way.
LS2 = -8
Until the maximum pressure has been reached, the tolerance
range changes by -8 bar in a linear way.
SP2 = -1
OU2 = Hnc
Output 2 is to switch (= ON) when the valve pressure is more
than 1 bar below the preset pressure.
Note: the hysteresis (rP2) has to be taken into account.
