Meanings Of Signals; Limit Input Signals - Contec SMC-8DL-PCI User Manual

4. Functions

Meanings of signals

Limit input signals

Limits switches are used to detect the position of the carrier in a positioning system using a stepping
motor to stop the motor when the carrier has reached the target position (final destination). This product
is also provided with the slow-down stop input to slow down the high-speed rotation at acceleration or
deceleration. The mounting position of each limit switch is shown below.
Connection
Pulse motor carrier
part
Negative Positive
+LIM
-LIM SD ORG SD
(CCW) (CW)
Figure 4.1. The attachment position relation of a limit switch
+LIM (Positive-direction end limit input), -LIM (Negative-direction end limit input)
Place +LIM at the end position when the stepping motor rotates clockwise (CW) and -LIM at the end
position when the stepping motor rotates counterclockwise (CCW). When the carrier reaches either
position (the limit input is turned on), the motor stops immediately unconditionally. Even when a
subsequent operation directive (instruction) for moving in the same direction is issued, the carrier won't
move forward beyond the limit position as long as the limit has been applied. The motor restarts
operation (rotation) in response to an operation directive for moving in the opposite direction.
The logical direction can be set by software.
SD (deceleration (decelerated stop) input)
SD is a limit input to detect the position at which to start deceleration during high-speed rotation
(accelerating/decelerating operation). The carrier operating (moving) at high speed starts deceleration at
that position and stops after slowing down to the initial speed. The logical direction can be set by
software.
ORG (origin input)
ORG is the switch input to detect the origin to be set as the base point for each operation. The logical
direction can be set by software.
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SMC-4DL-PCI, SMC-8DL-PCI