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PQP-171-P
5.6.4
PWM (PWM Frequency)
Command
Parameter
Unit
Group
PWM
X
x= 61… 2604
Hz
STD
The frequency can be changed in defined steps (61 Hz, 72 Hz, 85 Hz, 100 Hz, 120 Hz, 150 Hz, 200 Hz, 269
Hz, 372 Hz, 488 Hz, 624 Hz, 781 Hz, 976 Hz, 1201 Hz, 1420 Hz, 1562 Hz, 1736 Hz, 1953 Hz, 2232 Hz and
2604 Hz). The optimum frequency depends on the valve.
Attention: The PPWM and IPWM parameters should be adapted when using low PWM frequencies
because of the longer dead times which forces a reduced stability of the closed loop control.
5.6.5
ACC (Current loop auto adjustment)
Command
Parameter
Unit
Group
ACC
X
x= ON|OFF
-
EXP
Operation mode of the closed loop current control.
ON
:
In automatic mode PPWM and IPWM are calculated depending on the preset PWM-frequency.
OFF
:
Manual adjustment.
5.6.6
PPWM (P gain of the current loop)
5.6.7
IPWM (I gain of the current loop)
Command
Parameters
Unit
Group
PPWM
X
IPWM
X
x= 0… 30
x= 1… 100
-
-
EXP
The PI current controller for the solenoids is parameterized with these commands.
CAUTION
: These parameters should not be changed without adequate measurement facilities and
experience.
Attention
, if the parameter ACC is set to ON, these adjustments are done automatically.
If the PWM frequency is < 250 Hz, the dynamic of the current controller has to be decreased.
Typical values are: PPWM = 1… 3 and IPWM = 40… 80.
If the PWM frequency is > 1000 Hz, the default values of PPWM = 7 and IPWM = 40 should be chosen.
