7 Before Starting Positioning Operation
82
FX
3U
-20SSC-H Positioning Block User's Manual
7.3 Handling the Forward Rotation Limit and Reverse Rotation Limit
7.3
Handling the Forward Rotation Limit and Reverse Rotation Limit
The concept of the forward rotation limit and that of the reverse rotation limit are described. Suppose that limit
switches are located as shown in the figure below.
*1.
Sudden stop or deceleration stop can be selected with Ver.1.20 or later.
→
For details, refer to Section 7.5
Note
• The 20SSC-H does not have a terminal for connecting the forward or reverse rotation limit switch.
Connect the forward and reverse rotation limit switches to the PLC and/or servo amplifier.
• Provide the forward/reverse rotation limit when using the DOG search function in a DOG type mechanical
zero return. The DOG search function operates, even if the forward/reverse rotation limit are provided in
either a PLC or the servo amplifier side.
How to restart after the limit switch is activated
When the limit switch is activated, the work piece decelerates to stop, and a limit error occurs.
The work piece cannot move to the activated limit-switch side. Use the JOG operation in opposite direction or
the manual pulse generator in the opposite direction to avoid the limit error.
Limit
Stopping
action
Description
Reference
Servo
amplifier
Forward
rotation limit 2,
reverse
rotation limit 2
Deceleration
to stop
*1
Specify the action limit so that no damage is caused to the machine that
decelerates to stop after activation of the limit switch.
Subsection
7.3.1
PLC
Forward
rotation limit 1,
reverse
rotation limit 1
Deceleration
to stop
*1
Provide at positions so that the limit switch is activated before forward
rotation limit 2 or reverse rotation limit 2 connected with the servo
amplifier.
Subsection
7.3.2
Software limit (upper)
Software limit (lower)
Deceleration
to stop
*1
Operation limit based on the current address that is effective after
mechanical zero return.
Specify at addresses where activation is caused before the forward
rotation limit 1 or reverse rotation limit 1 connected with the PLC.
Subsection
7.3.3
LSR
Reverse rotation limit 2
(servo amplifier side)
Reverse rotation limit 1
(PLC side)
LSF
Forward rotation limit 1
(PLC side)
Forward rotation limit 2
(servo amplifier side)
Servomotor
Reverse rotation
Forward rotation
ON
OFF
Operation speed
Deceleration to stop
However, immediate stop is caused during
operation with the manual pulse generator.
Forward rotation limit input
Reverse rotation JOG operation or reverse rotation
manual pulse generator operation is valid.
Forward rotation JOG operation or forward
rotation pulse generator operation is invalid.