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Moog Animatics SmartMotor™ Developer's Guide, Rev. L
Page 334 of 909
BRKTRJ
Brake Trajectory, Engage When No Active Trajectory
APPLICATION:
Motion control
DESCRIPTION:
Release hardware brake while a trajectory is in progress;
engage hardware brake while no trajectory is in progress
EXECUTION:
Immediate; remains in effect until otherwise commanded
CONDITIONAL TO:
Hardware brake option is required
LIMITATIONS:
None
READ/REPORT:
N/A
WRITE:
N/A
LANGUAGE ACCESS:
N/A
UNITS:
N/A
RANGE OF VALUES:
N/A
TYPICAL VALUES:
N/A
DEFAULT VALUE:
FIRMWARE VERSION:
5.x and later
COMBITRONIC:
BRKTRJ:3
where ":3" is the motor address — use the actual address or a
variable
DETAILED DESCRIPTION:
The SmartMotor™ may be purchased with optional, internal, zero-backlash brakes, which are
used to hold a load for safety purposes. They are fail-safe, magnetic-clutch, disk brakes. The
default power-on state is to disengage the brake when the drive stage is turned on. When
power is lost, the brake engages. The brake takes from 3 to 5 milliseconds to actuate or
release.
BRKTRJ automatically coordinates movement and brake application. When a trajectory is
started by a G command, the brake is released. When the trajectory completes, the brake is
engaged and the servo is simultaneously turned off. In this mode, and whenever the motor is
not performing a trajectory, the brake is automatically engaged and the servo is turned off for
any reason that clears the Bt (Busy Trajectory) bit.
As a result, any non-trajectory mode, like Torque mode, will not result in motion because the
brake will be engaged and the servo will be off. Because the motor-off flag Bo is 0 (false), this
behavior could be confusing to a user who is unaware of the function of BRKTRJ. However,
from an operation/control perspective, the motor has not changed modes to OFF, which would
be coincidental with Bo set to 1. When running in Torque mode or some other non-trajectory
mode, it is more appropriate to use BRKSRV. For details, see BRKSRV on page 332.
BRKTRJ terminates the brake control modes BRKRLS, BRKENG and BRKSRV.
BRKTRJ immediately resets the trajectory flag to zero when the trajectory generator declares
the trajectory has completed. At that instant, the BRKTRJ will engage (de-energize) the brake.
Part 2: Commands: BRKTRJ