Geschäftsführer: Dr. Bernt Götz • Telefon 03641/66880 • Fax 03641/668866 • www.piezosystem.com
37
10 controller adjustment
When any actuator made by
piezosystem jena
is connected to the
24DV40
, amplifier their specific
values are read from the actuator
’s ID-chip. The Digital Signal Processor (DSP) of the amplifier is
set with these values. These parameters were investigated in the
piezosystem jena
laboratory
and ensure safe function of the actuator.
There are no kp-, ki-, and kd-values for actuators without a measurement system because the
closed loop mode is impossible in this configuration. Closed loop is automatically switched off.
To adapt the controller properties to your special application please start with the default values. At
first please switch on the closed loop mode by the command
cl,1
. Change one parameter step by
step and check the result. Maybe there is an additional external position sensor required.
In general, change the parameters in small steps and, depending on the actuator's reaction,
slightly increase the step width. If the system begins to oscillate, switch off the closed loop (cl,0),
then reset the last values entered!
Low dynamic applications need only an integral term in PID-controller, its set by parameter ki, (kp
und kd can be set 0). For filtering the set point, a slew rate limiter (command sr) is implemented.
The limit is given in % / ms, it means, that a value of 1 %/ms would realize, that a jump off the full
range (100
%) is converted to a ramp with 100
ms duration. The devices maximum slew rate
depends on maximum output current and the actuators capacity. Independent from the sr value,
this maximum slew rate cannot be exceeded.
To filter higher frequency parts on the input signal (in region to the resonant frequency or higher), a
low pass filter 4
th
order is implemented. It can be activated or deactivated by the command
lpon,1/0. The cut of frequency can be set by command lpf,value.
11 troubleshooting
Please check all cables and connections first if the system is not working properly.
error
possible solution
LED lights red
Check the connection between actuator and amplifier.
Check the actuator cable for damage.
actuator oscillates in
resonant frequency in
closed loop
Check the PID-controller adjustments, reduce the ki-value,
Reduce the kd-value.
no communication by USB
is possible
-
plug out and re plug in the USB cable, restart or reconnect
the terminal application
-
check the device manager for a loaded USB driver
-
check the interface settings:
-
115200
baud, 8
bits, 1 stop bit, no parity, software
handshake (if applicable)
Regardless the USB interface, the correct baud rate is necessary
to set.
table: possible error causes
