Moog Animatics SmartMotor™ Developer's Guide,Rev. L
Page 419 of 909
EL=formula
Error Limit
APPLICATION: Motion control
DESCRIPTION: Set maximum allowable position error (the error limit)
EXECUTION: Immediate; enforced each PID sample
CONDITIONAL TO: Servo active (MP, MV, etc., not MT mode)
LIMITATIONS: Torque mode has no position error
READ/REPORT: REL
WRITE: Read/write
LANGUAGE ACCESS: Assignment, formulas and conditional testing
UNITS: Encoder counts
RANGE OF VALUES: 0 to 262143
TYPICAL VALUES: 1000
DEFAULT VALUE: 1000
FIRMWARE VERSION: 5.x and later
COMBITRONIC: EL:3=1234
where ":3" is the motor address — use the actual address or a
variable
DETAILED DESCRIPTION:
The EL command is used to set the maximum allowable position error in encoder counts.
Position error is the difference between the calculated trajectory position (PC), at any instant
in time, and the actual position (PA). The SmartMotor™ uses the position error to generate a
torque by means of the PID filter. The greater the error or deflection, the more torque the
motor applies in attempt to correct it.
CAUTION: An EL setting that is greater than the expected move distance may
result in drive saturation and severely limit the life of the SmartMotor.
EL is primarily used as a safety measure. It is a programmable, allowable error beyond which
the motor recognizes it is outside of the domain of control being enforced. If EL=100 is
commanded and a position error of greater than 100 encoder counts occurs, the motor will
perform its fault reaction and the Be (Position Error bit) will be set to 1. All closed-loop modes
are bound by this EL value. Non-closed-loop modes, such as Torque mode, ignore the value of
EL.
EXAMPLE:
EL=1234'Set maximum allowable error to 1234
If the motor dynamically exceeds 1234, it immediately faults on position error.
Part 2: Commands: EL=formula
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