Allen-Bradley ControlLogix Reference Manual

CIP Axis Attributes
Chapter 4
Rockwell Automation Publication MOTION-RM003I-EN-P - February 2018 405
The PM Motor Linear Voltage Constant attribute is a floating point value that
specifies the voltage, or back-EMF, constant of a linear permanent magnet motor
in phase-to-phase RMS Volts per meter/sec.
If the optional PM Motor Force Constant, Kf, is not explicitly supported in the
implementation, the value may be computed from the PM Motor Linear Voltage
Constant, Ke, according to this equation: Kf (N/A
rms
) = 1.732 * Ke (V
rms
/(m/s))
PM Motor Linear Bus Overvoltage Speed
Usage Access Data
Type
Default Min Max Semantics of Values
Optional - PVT
(PM Only)
Set/GSV REAL 0
FD
0
m/s
The PM Motor Linear Bus Overvoltage Speed attribute value corresponds to the
linear motor speed at which the back-EMF of the motor equals the maximum
operational bus voltage of the drive. When the extended speed range of a PM
motor is not permitted (PM Motor Extended Speed Permissive is False), this value
can be used to limit motor speed to protect the drive from damage due to bus
overvoltage conditions that can occur when disabling a PM motor at high speed.
When configured for Position Loop or Velocity Loop operation, this bus
overvoltage protection includes limiting the magnitude of the velocity reference
value allowed into the velocity summing junction to the Bus Overvoltage Speed
Limit value using the velocity limiter function. If the signal entering the velocity
limiter exceeds this velocity limit value, and the PM Motor Extended Speed
Permissive is False, the velocity limiter clamps the velocity reference to this value
and sets the Velocity Limit status bit. If the PM Motor Extended Speed Permissive
is True, or the value of this attribute is 0, this limit is not applied.
When the extended speed range of a PM motor is not permitted, overvoltage
protection is also provided through motor overspeed detection based on the
Motor Overspeed Factory Limit and Motor Overspeed User Limit. Exceeding
these limits results in a Motor Overspeed FL or UL Axis Exception. Overspeed
detection is the only source of protection when the axis is configured for Torque
Loop operation.
PM Motor Linear Max Extended Speed
Usage Access Data
Type
Default Min Max Semantics of Values
Optional - PVT
(PM Only)
Set/SSV REAL 0
FD
0 or
Linear
Motor
Max
Speed
m/s

Allen-Bradley ControlLogix Specifications

General

Brand	Allen-Bradley
Model	ControlLogix
Category	Industrial Electrical
Language	English