5.11 Overtravel Function and Settings
5.11.1 Overtravel Signals
5-28
5.11
Overtravel Function and 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 Input) and the N-OT (Reverse
Drive Prohibit Input) signals. You use the P-OT and N-OT signals to stop the machine by install-
ing limit switches at the positions where you want to stop the machine that is operated by the
Servomotor.
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.
5.11.1
Overtravel Signals
The overtravel signals include the P-OT (Forward Drive Prohibit Input) and the N-OT (Reverse
Drive Prohibit Input) signals.
You can operate the Servomotor in the opposite direction during overtravel by inputting a refer-
ence.
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 Output) 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 Pn001 to n.
1
to
place the Servomotor in a zero-clamped state when it 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 Pn001 to n.
1
to place the Servomotor in a zero-clamped state
when it stops.
Limit
s
witch
S
ervomotor
4, 10
CN1
3
, 9
P-OT
N-OT
Limit
s
witch
Forward direction of motor
S
ERVOPACK
Rotary
S
ervomotor
Limit
s
witch
S
ervomotor
CN1
P-OT
N-OT
Limit
s
witch
4, 10
3
, 9
Forward direction
S
ERVOPACK
Linear
S
ervomotor
s
Type
Signal
Connector Pin No.
Signal
Meaning
Input
P-OT
Axis A: CN1-3
Axis B: CN1-9
ON
Forward drive is enabled (normal operation).
OFF
Forward drive is prohibited (forward over-
travel).
N-OT
Axis A: CN1-4
Axis B: CN1-10
ON
Reverse drive is enabled (normal operation).
OFF
Reverse drive is prohibited (reverse over-
travel).
