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3 BASIC FUNCTION
3.4 Stroke limit function [G] [WG]
3.4
Stroke limit function [G] [WG]
The stroke limit function is a function that limits the travel distance of servo motors. On a system configuration where the
movable range is limited, wire the stroke limit signal and use this function to prevent machine damage due to a collision.
When the stroke limit signal is detected, a warning regarding the detected signal occurs, and the servo motor stops based on
the stop method described in this section.
When a system configuration without the limited movable range is used and therefore the stroke limit function is not
necessary, set the stroke limit signal to always on.
• The stroke limit signal cannot be used in the torque mode. In the torque mode of the linear servo motor and
the direct drive motor, the stroke limit signal can be used only at the time of magnetic pole detection.
• In the continuous operation to torque control mode, the stroke limit signal is available only when the
magnetic pole is detected using a linear servo motor or direct drive motor. The stroke limit signal will be
unavailable after the magnetic pole detection is completed.
Precautions
• The stroke limit signal is the signal for a normally closed contact. The limit is released when the contact is on (shorted), and
the limit is in progress when the contact is off (open).
• Depending on the stop method setting of the stroke limit and the commands from the controller, the home position may be
erased when the servo motor is stopped by the stroke limit signal being detected during operation. If the home position is
erased, perform homing again.
Explanation of the stroke limit signal names
There are two sets of stroke limit signals: FLS (Upper stroke limit)/RLS (Lower stroke limit) and LSP (Forward rotation stroke
end)/LSN (Reverse rotation stroke end). The characteristics of both signals are shown in the following table. The signal
names differ depending on whether the stroke limit signal is used on the controller or on the servo amplifier. Use the signal
that is appropriate for the system configuration being used.
To wire limit switches to the servo amplifier, wire the limit switch installed in CCW direction to LSP (Forward rotation stroke
end), and wire the limit switch installed in CW direction to LSN (Reverse rotation stroke end).
To wire limit switches to the controller, wire the limit switch installed in the increasing direction of the positioning address to
FLS (Upper stroke limit), and wire the limit switch installed in the decreasing direction to RLS (Lower stroke limit). Then, input
the signals from the controller.
Name
Symbol
Purpose of the signal
Upper stroke limit
FLS
The limit signal which suppresses the operation in the positioning address increasing direction with regard to the
command from the controller
Lower stroke limit
RLS
The limit signal which suppresses the operation in the positioning address decreasing direction with regard to the
command from the controller
Forward rotation stroke end
LSP
The limit signal which suppresses the operation in the servo motor CCW direction or in the linear servo motor
positive direction
Reverse rotation stroke end
LSN
The limit signal which suppresses the operation in the servo motor CW direction or in the linear servo motor
negative direction
