Lenze PositionServo 940, User Manual

Page: 44 / 68

S94P01B
42
6.6.2 Hard limit switch action
Digital inputs IN_A1-IN_A2 can be used as limit switches if their function is set to
“Fault” or “Stop and Fault”. Activation of this input while the drive is enabled will cause
the drive to Disable and go to a Fault state. The “Stop and Fault” action is available
only in Position mode when the “Reference” parameter is set to “Internal” i.e. when
the source for the motion is the Trajectory generator. See Programmer’s Manual for
details on “Stop and Fault” behavior.
6.7 Velocity Limits Group
These parameters are active in Velocity Mode Only.
6.7.1 Zero Speed
Specifies the upper threshold for motor zero speed in RPM. When the motor shaft
speed is at or below the specified value the zero speed condition is set to true in the
internal controller logic. The zero speed condition can also trigger a programmable
digital output, if selected.
6.7.2 Speed Window
Specifies the speed window width used with the “In speed window” output.
6.7.3 At Speed
Specifies the speed window center used with the “In speed window” output.
These last two parameters specify speed limits. If motor shaft speed is within these
limits then the condition AT SPEED is set to TRUE in the internal controller logic. The
AT SPEED condition can also trigger a programmable digital output, if selected.
For example if “AT SPEED” is set for 1000 RPM, and the “SPEED WINDOW” is set for
100, then “AT SPEED” will be true when the motor velocity is between 950 -1050 RPM.
6.8 Position limits
6.8.1 Position Error
Specifies the maximum allowable position error in the primary (motor mounted)
feedback device before enabling the “Max error time” clock (described next). When
using an encoder, the position error is in post-quadrature encoder counts. When using
a resolver, position error is measured at a fixed resolution of 65,536 counts per motor
revolution.
6.8.2 Max Error Time
Specifies maximum allowable time (in mS) during which a position error can exceed
the value set for the “Position error” parameter before a Position Error Excess fault is
generated.
6.8.3 Second Encoder Position Error
Specifies the maximum allowable error of the second encoder in post quadrature
encoder counts before enabling the “Second encoder max error time” clock (described
next).
6.8.4 Second Encoder Max Error Time
Specifies maximum allowable time (in mS) during which the second encoder’s position
error can exceed the value set for the “Second encoder position error” parameter
before a Position Error Excess fault is generated.