11
CD1-k – User Guide
Chapter 2 – Commissioning
4.2.2 - CURRENT LIMITATION IN "LIMITING" MODE
When the amplifier output RMS current (I
2
t) reaches 85 % of the rated current, the
OK
LED on the amplifier front
panel is blinking. When the RMS current (I
2
t) drops below 85 % of the rated current, the blinking is inhibited.
When the amplifier output RMS current (I
2
t) reaches the rated current value, the I
2
t protection limits the amplifier
output current at this value.
Diagram of the amplifier output current limitation in an extreme case (motor overload or shaft locked):
The maximum current duration before release of the blinking display (t1 - t0) and before limitation at the rated
current (t2 - t0) is calculated the same way as in the "Fusing" mode.
4.3 - SERVO LOOP ADJUSTMENT
4.3.1 - REGULATOR PARAMETERS
The
Autotuning
procedure identifies the motor and load specifications and calculates the speed/position loop
parameters.
In
P
and
PI
speed mode, only the speed loop gains are calculated.
In
PI
2
speed mode, the proportional gain of the position loop is also calculated. But the
Feedforward
gains of the
position regulator are all initialized at 0.
In
Position
mode, all gains of both speed
and
position regulators are calculated.
Note: The position loop stability can be tested in
PI
² speed mode because the
Feedback
gains are identical to the
Position
mode.
The operator can select a bandwidth (
Low
,
Medium
or
High
) as well as the filter type (
standard
,
antiresonance
or
max. stiffness
).
The
Autotuning
procedure can be executed with the motor disabled or enabled (i.e. vertical load).
Before executing the
Autotuning
procedure, check that the motor shaft is free and that its rotation over one
revolution is not dangerous for operator and machine. Check that the brake is released (the
Autotuning
command does not control the brake).
For a complete adjustment, the
Autotuning
procedure must
always
be executed in
Position
mode (at power on,
the amplifier is automatically in
Position
mode).
But the amplifier position loop stability can also be tested in
Speed
mode. In this case, after the execution of the
Autotuning
procedure in
PI²
mode:
•
check that the motor is correctly running in both directions,
•
check
the
response at a small displacement without I
dc
saturation
(oscilloscope function).
In case of loud noise in the motor at standstill or when running, check the rigidity of the mechanical transmission
between motor and load (backlashes and elasticities in motor and couplings).
If required, start a new
Autotuning
procedure by selecting a lower bandwidth.
If the instability remains, start a new
Autotuning
procedure by activating the
Antiresonance
filter. If necessary,
adjust more accurately the loop response stability by adjusting the stability gain.
Amplifier output current
Max. current
Rated current
time
t0
t1 = Blinking
t2 = Current limitation
t2
t1
