Справочник Пользователя для Delta Tau GEO BRICK LV
Turbo PMAC User Manual
212
Making your Application Safe
Two I-variables control the functioning of the I
2
T protection for each motor. Ixx57 is the continuous
current limit magnitude. It has the same units as the Ixx69 instantaneous output limit, bits of a 16-bit
DAC (even if some other output device is used). Both have a maximum magnitude of 32,767, which is
the size of Turbo PMAC’s maximum possible output. If Ixx57 is a positive value, I
DAC (even if some other output device is used). Both have a maximum magnitude of 32,767, which is
the size of Turbo PMAC’s maximum possible output. If Ixx57 is a positive value, I
2
T protection will be
used; if Ixx57 is a negative number, |I|T protection will be used. Generally Ixx57 will be 1/4 to 1/2 of the
magnitude of Ixx69.
magnitude of Ixx69.
Ixx58 is the integrated current limit parameter. If Ixx58 is set to 0, this function is disabled. If Ix58 is
greater than 0, Turbo PMAC will compare the integrated current value to Ixx58. When the integrated
current value exceeds this value, Turbo PMAC will fault this motor as if an amplifier fault had occurred.
The offending motor is killed; if it was in a coordinate system running a motion program, that motion
program aborted; other motors are killed according to the setting of bits 21 and 22 of Ixx24.
Turbo PMAC’s I
greater than 0, Turbo PMAC will compare the integrated current value to Ixx58. When the integrated
current value exceeds this value, Turbo PMAC will fault this motor as if an amplifier fault had occurred.
The offending motor is killed; if it was in a coordinate system running a motion program, that motion
program aborted; other motors are killed according to the setting of bits 21 and 22 of Ixx24.
Turbo PMAC’s I
2
T function works according to the following equation:
t
2
32768
57
Ixx
2
32768
d
I
2
32768
q
I
Sum
Sum
∆
−
+
+
=
Turbo PMAC’s |I|T function works according to the following equation:
t
32768
57
Ixx
32768
d
I
32768
q
I
Sum
Sum
∆
−
+
+
=
where:
I
q
(quadrature current) is the commanded torque-producing output of the PID filter in units of a 16-
bit DAC;
bit DAC;
I
d
(direct current) is the magnetization current command as set by Ixx77. This is usually zero
except when Turbo PMAC is doing vector control of induction motors.
except when Turbo PMAC is doing vector control of induction motors.
∆t
is the time since the last sample in servo cycles
If Sum exceeds Ixx58, an integrated-current fault will occur. When commanded current levels are below
Ixx57, Sum will decrease, but it will never go below zero.
Ixx57, Sum will decrease, but it will never go below zero.
PMAC I
2
T Protection Feature
I
2
T Fault
2
I
2
I
Normalized
Saturation
Integrator
Charge-Up
Integrator
Discharge
2
32768
Ix57
2
Ix57
2
32768
Ix69
2
Ix69
2
0
.
1
2
32768
time
(servo cycles)
~
~
~
~
Example: With command output limit Ixx69=32767 (maximum), integrated current limit Ixx57=16384
(half of maximum), and magnetization current Ixx77=0, the motor hits an obstruction, and the command
output saturates at 32767. The integrated-current protection function will calculate during this time:
(half of maximum), and magnetization current Ixx77=0, the motor hits an obstruction, and the command
output saturates at 32767. The integrated-current protection function will calculate during this time: