5.10 Overtravel and Related Settings
5.10.1 Overtravel Signals
5-27
5
Basic Functions That Requir
e Setting befor
e Operation
5.10
Overtravel and Related Settings
Overtravel is a function of the SERVOPACK that forces the Servomotor to stop in response to a
signal input from a limit switch that is activated when a moving part of the machine exceeds the
safe range of movement.
The overtravel signals include the P-OT (Forward Drive Prohibit) and the N-OT (Reverse Drive
Prohibit) signals.
You use the P-OT and N-OT signals to stop the machine by installing limit switches at the posi-
tions where you want to stop the machine that is operated by the Servomotor.
Even during overtravel, you can input a reference to drive the motor in the opposite direction.
A SERVOPACK wiring example is provided below.
Using the overtravel function is not necessary for rotating applications such as rotary tables
and conveyors. No wiring for overtravel input signals is required.
This section describes the parameters settings related to overtravel.
5.10.1
Overtravel Signals
The overtravel signals include the P-OT (Forward Drive Prohibit) and the N-OT (Reverse Drive
Prohibit) signals.
Even during overtravel, you can input a reference to drive the motor in the opposite direction.
CAUTION
To prevent accidents that may result from contact faults or disconnections, use normally
closed limit switches.
Do not change the default settings of the polarity of the overtravel signals (P-OT and N-OT).
If you use a Servomotor for a vertical axis, the /BK (Brake) signal will remain ON (i.e., the
brake will be released) when overtravel occurs. This may result in the workpiece falling when
overtravel occurs. To prevent the workpiece from falling, set PnB1F to 0001h or 0002h so
that the servo is locked when the Servomotor stops.
A base block state is entered after stopping for overtravel. This may cause the Servomotor
to be pushed back by an external force on the load shaft. To prevent the Servomotor from
being pushed back, set PnB1F to 0001h or 0002h so that the servo is locked when the Ser-
vomotor stops.
9
CN1
8
P-OT
N-OT
Rotary Servomotors
Servomotor
Limit
switch
Limit
switch
SERVOPACK
Forward direction of motor
9
CN1
8
P-OT
N-OT
Linear Servomotors
Servomotor
Forward direction
SERVOPACK
Limit
switch
Limit
switch
Type
Signal
Connector Pin No.
Signal Status
Meaning
Input
P-OT
CN1-8
ON
Forward drive is enabled (actual operation).
OFF
Forward drive is prohibited
(forward overtravel).
N-OT
CN1-9
ON
Reverse drive is enabled (actual operation).
OFF
Reverse drive is prohibited
(reverse overtravel).