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SCU-138-P-2230
5.6 Power stage
5.6.1
CURRENT (Rated solenoid current)
Command
Parameters
Unit
Group
CURRENT
X
x= 500… 2600
mA
STD
The nominal current (for 100% opening) of the solenoid is set here. Dither and also MIN/MAX always refer to
this current value.
5.6.2
DFREQ (Dither frequency)
5.6.3
DAMPL (Dither amplitude)
Command
Parameters
Unit
Group
DFREQ
X
DAMPL
X
x= 60… 400
x= 0… 3000
Hz
0.01 %
STD
The dither
2
can be defined with this commands. Different amplitudes or frequencies may be required
depending on the valve. The dither amplitude is defined in % (peak to peak value) of the nominal output cur-
rent (see: CURRENT command). The dither frequency is defined in Hz. Depending on the internal calcula-
tions, the frequency is adjustable in steps only.
CAUTION: The PPWM and IPWM parameters influence the effect of the dither setting. These
parameters should not be altered again after the dither has been optimized.
CAUTION: If the PWM frequency is less than 500 Hz, the dither amplitude DAMPL should be set to
zero.
2
The dither is a ripple signal which is superimposed on the current set point and is defined by the amplitude and fre-
quency: the dither frequency and the PWM frequency.
The dither frequency should not be confused with the PWM fre-
quency
.
In some documentations the PWM frequency is described as a dither. This can be recognized by the lack of the
dither amplitude.