Continental Hydraulics Installation Manual
Page 23 of 24
CEM-PA-B
CHI 1020688 01/2016
FAULT
CAUSE / SOLUTION
ENABLE is active, the
READY LED is active and
the pressure is instable.
In many cases you may have a hydraulic problem.
Electrical problems may be:
Electrical noise at the wire of the power supply.
Very long solenoid wiring (> 40 m), disturbance in the current control
loop
6
.
Unstable current control loop. The adjustments of the PWM-frequency and
the dither (frequency and amplitude) have to be checked carefully. Good
experiences are made with:
a. PWM-frequency = 2600 Hz (higher frequency), the dither has to be
aligned to the valve (amplitude and frequency).
b. PWM-
frequency = 100… 400 Hz (lower frequency), the dither
amplitude is set to 0 % (disabled)
7
.
ENABLE and START
(PIN 6) are active,
READY LED is ON, the
pressure control works,
but the pressure is not
equal to the command
input.
The system works generally, but wrong control loop settings or wrong
adjustment of the input signals cause control errors.
1. The feedback pressure is proportional to the command input pressure, but
the values are too high or too low.
The scaling of the pressure valve is affected by the adjustment of
the output current and the parameter
MAX
.
The valve has a nominal range of 320 bar and the working
pressure range is 240 bar, the parameter MAX has to be
decreased. Procedure: Deactivate PIN 6, set the command input
to 100 % and adjust the correct pressure by reducing the
MAX
parameter.
6
Maybe you have to adjust / optimize the solenoid control loop (P and I).
7
In most applications (particularly pressure-actuated pumps) with pressure valves a lower PWM-frequency
is the better solution.
