ElmoMC SimplIQ Software Manual User Manual
Page 222
SimplIQ
Software Manual
The Controller
MAN-SIMSW (Ver. 1.4)
15-4
K
SPEED
is the conversion factor from the D/A scale to current in amperes:
BITS
VALUE
MC
MC
K
Speed
_
_
=
,
14000
_
_
=
BITS
VALUE
MC
otherwise
count
GS
dt
e
and
samples
GS
for
counts
encoder
no
if
t
p
SPEED
]
14
[
32768
1
]
0
[
1
0
)
(
<
⎩
⎨
⎧
=
∫
For a non-schedule case:
K
P
= KP[2]
K
I
= KI[2]
The scheduled case is explained in
The GS[0] parameter is used to stabilize the motion at very low speeds. It cuts the
proportional gain of the speed controller after enough controller sampling times have
elapsed without a change in the encoder readout.
Example:
For a speed reference of 200 counts/second, a new encoder count is available once per 5
milliseconds, which is about 25 sampling times of the speed controller. If a new encoder
pulse comes only once per 5 milliseconds, the speed readout is delayed by at least 2.5
milliseconds, which in turn may have a fatal effect on the control stability. Setting GS[0]=12,
the proportional gain of the controller is applied only for about half of the time, leading to a
practical reduction of the proportional gain to half at that speed. The reduced gain implies
reduced bandwidth and increased stability. The acceleration from complete rest is slow. To
avoid cutting the speed proportional gain, set GS[0] to its maximum value (refer to the GS
command section in the
SimplIQ
Command Reference Manual).
The parameters of the non-scheduled speed controller are:
Parameter Description
KP[2] Proportional
gain
KI[2] Integral
gain
GS[0]
Proportional gain duration
GS[2]
Controller gain selection
GS[14]
Speed reference integral threshold
FF[1] Torque
feed
forward
CL[1]
Continuous torque limit
PL[1] Peak
torque
limit
KV[N] High-order
filter
parameters
Table
15-3: Non-scheduled Speed Controller Parameters