91
NTT 240/460
Operation mode
Installation and user guide
Rev: 4.0
During disengaging brake, drive provides to keep motor rated torque/current. When brake contact is really
disengage, drive provides load proper torque/current in order to hold it until ‘time brake disable’ set is expired.
During disengaging brake, any axis movements may occur, because of mechanical brake disable time and drive
PID regulator smartness. For this reason, “Current Offset” parameter is available for pre-applying torque to motor
during the brake disable time, in order to avoid axis movements when PID regulators start to operate.
To use correctly the pre-torque function, follow the instruction below:
•
set “Current Offset” parameter to 0.
•
disengage brake and read the current value provided by the drive to keep load.
•
write the current value (with sign value) into “Current Offset” parameter.
The timing-chart for motor brake function is described in the image below:
1
2
3
3
1
2
Enable
Time
Stop ramp
External
Speed
Reference
Target
Speed
Output for
motor brake
(OUT-x)
Enable/engage condition for motor brake
1 SWITCH-OFF command and stop-ramp perform
2 Enable motor blake and drive in SWITCH-ON
3 Drive in SWITCH-OFF
Disable
Time
Speed
Reference
Output for
motor brake
(OUT-x)
Disable/disengage for motor brake
1 Command for SWITCH-ON + brake disable
2 Disable time is over and drive is ready to
OPERATION ENABLED
3 Command for OPERATION ENABLED
Drive in
SWITCH-ON
Drive in
OPERATION ENABLED
Drive in
SWITCH-OFF
Drive in
SWITCH-ON
Drive in
OPERATION ENABLED
Drive in
SWITCH-OFF
Speed reference generated by drive to perform
braking procedure
Output brake function setting and parameter described above are shown in the image below:
!
NOTES:
•
Drive performs stop following speed reference, not measured speed, in order to engage motor brake
also during power stage failure conditions.
•
Motor brake function is not available during torque control.
•
To ensure that pre-torque function works properly, it’s necessary that vertical axis load should be quite
constant during all machine working cycle.
Содержание NTT 240
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