CNC Setup Utility Manual
P/N 70000490C - Machine Constants
2-18
All rights reserved. Subject to change without notice.
10-December-04
Table 2-2, Machine Constants Setup
(Continued)
Machine Constant
Parameter
Function Settings
MC_2020:
X Current Control
Gain N<Nom (mV/A)
The X-axis current control (PI) gain is
determined with MC_2020. Both P
(Proportional) and I (Integral)
components can be determined with
just one machine constant.
Range (16–999999)
60000 (mV/A) [Default]
MC_2021:
X Current Control
Gain N>Nom (mV/A)
The X-axis current gain control usually
has to be increased for revolutions
above Nnom. The gain of MC_2021 is
defined at Nmax. When MC_2021 is
set at zero, the gain of MC_2020 is
applied for the whole speed range. The
gain between Nnom and Nmax is
increased linearly.
Range (0–999999)
0 (mV/A) [Default]
MC_2022:
X Vel. Control Prop.
Gain (mAs/rev)
The X-axis proportional gain of the
velocity control loop is set using the
velocity loop gain Kvel. The overall loop
gain depends on the machine constant
value, the motor torque constant, and
the equivalent mass moment of inertia
(related to the motor).
Range (0.1–10000.0)
2.0 (mAs/rev) [Default]
MC_2023:
X Vel. Control Integral
Timecons (.1ms)
X-axis velocity control integral time
constant in tenths of milliseconds.
Range (0.000–100.000)
0.100 (0.1ms) [Default]
MC_2024:
X Vel. Control Integral
Limit (ms)
If the X-axis “limit cycling” effect occurs
during rest, limiting the integral buffer
can compensate it. This compensation
is switched off when MC_2024 = 0.
Realistic input values are between
100–200 milliseconds.
Range (0.00–1000.00)
0.00 (ms) [Default]
MC_2025:
X Vel. Control Diff.
Gain (.1mAs2/rev)
Normally the X-axis differential gain is
not used in the speed controller. The
differential gain reduces oscillations in
the low frequency range (<200 Hz), but
it destabilizes the controller in the higher
frequency range.
Do not use this constant for machine
axis if the motor is coupled to the
spindle via a timing belt.
Range (0.00–1000.00)
0.00 (0.1mAs
2
/rev) [Default]
MC_2026:
X Pos. Control Prop.
Gain (1/min)
Sets the X-axis positional control
proportional gain. The positional control
gain determines the dynamic servo
error for an axis without fast feed.
MC_2026 = 2000 [1/min],
feed = 2000 [mm/min], the dynamic
servo error is feed/MC_2024 = 1 [min].
Range (0.10–100.00)
40.00 (1/min) [Default]
(Continued…)
