6. Operation
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6.2.4. Software Over Travel Limit
This function is to set an off-limits area on the Motor rotation range.
Caution : F2 alarm is produced when the over travel is occurred.
The software over travel is detected based on the positioning command,
rather than the current Motor position. Positioning command is equal to
the sum of current position and position error.
Therefore, if the positioning command is not within the range of software
over travel detection, the F2 alarm is not produced even the actual motor
position is entered within the detection range due to the overshooting.
Caution : When the off-limits area should be controlled by the current position, it is
essential to set the hardware over travel limits.
Caution : When the software over travel limit is specified and when performing a
short cut positioning with the commands AD, AR, AQ (Absolute
positioning) under this state, the Motor turns into an opposite direction
not to enter the off-limits are regardless the positioning distance.
Refer to “8.6.3. Shorter Way Positioning” for to prevent going in the off-limits area.
Parameters OTP and OTM (Software travel limit) set the off-limits area. As shown in “Fig 6-4: Software
off-limits area” below, the parameters specify the off-limits area into counting up direction of position
scale from the point of the parameter OTP to the point of the parameter OTM.
The off-limits area becomes effective if the difference between the parameter OTP and OTM is one pulse
or more.
Fig 6-4: Software off-limits area
OTM: End of off-limits area
OTM: End of the off-limits area
OTP: Start of off-limits area
OTP: Start of off-limits area
If the Motor goes in the off-limits area, the System gets in the state of software over-travel.
The Motor stops immediately when it is moving in the direction towards the off-limits area.
In this state, the Motor only accepts the position command going out the off-limits area.
When the System goes in a state of software over travel, the outputs of OTPA and OTMA (Over travel
limit) will be closed.
Table 6-4: State of software over travel
If the current position is within the off-limits area at the power up, or servo-off state, the over travel limit
is stated to the nearest over travel limit.
If the current position is at the middle of travel limits between OTP and OTM, at the power up, or servo-
off state, the system assume the motor is entered from OTP side.
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