Filter
Top Products
FX
3G
/FX
3U
/FX
3UC
PLC User's Manual - Positioning Control Edition
Built-in Positioning Functions
4 Before Programming
4.3 Various Special Relays for Operation Commands
B - 48
4.3 Various Special Relays for Operation Commands
4.3.1 Forward Rotation Limit and Reverse Rotation Limit
When using the servo motor, the forward rotation limit and the reverse rotation limit can be set for the servo
amplifier.
To use the DOG search function for zero return, or to set the forward rotation limit or the reverse rotation limit
for operations other than zero return using the PLC, set the forward rotation limit 1 (LSF) and reverse rotation
limit 1 (LSR) for the PLC so that these limit switches can be activated before the forward rotation limit 2 or
reverse rotation limit 2 of the servo amplifier.
As shown in the following figure, interlock the forward rotation limit 1 (LSF) with the forward limit relay, and the
reverse rotation limit 1 (LSR) with the reverse limit relay. If the forward limit relay or the reverse limit relay turns
ON, the motor will perform operation depending on the output instruction as shown in the following
table.
Use the relays shown in the following table to determine the forward rotation limit and the reverse rotation limit
for each pulse output destination device (Y000, Y001, Y002, Y003).
*1. Y002 (pulse output destination) cannot be specified when the 14-point or 24-point type FX
3G PLC is
connected.
*2. Devices related to Y003 (pulse output destination) are only valid if two FX
3U-2HSY-ADP adapters are
connected to the FX
3U PLC.
*3. M8338 is supported in the FX
3U/FX3UC PLC Ver. 2.20 or later and FX3G PLC. If an FX3UC PLC is used
and its version is below Ver.2.20, the PLSV instruction will perform operation in the M8338 = OFF
mode (will perform operation without acceleration/deceleration).
*4. Only available for FX
3U and FX3UC PLCs.
Note:
If the forward rotation limit (LSF) and the reverse rotation limit (LSR) cannot be set, observe the following
items:
• Even if forward rotation limit 2 or reverse rotation limit 2 turns ON and the servo motor is automatically
stopped, the positioning instruction currently being activated cannot recognize the motor being stopped.
Therefore, pulses will be continuously output until the instruction is deactivated.
• The DOG search function of the DSZR instruction (zero return instruction with DOG search function)
cannot be used.
Pulse output
destination
device
Forward limit
relay
Reverse limit
relay
Corresponding instruction and stop
PLSV instruction
(M8338
*3
=OFF)
DSZR, DVIT
*4
, ZRN,
PLSV(M8338
*3
=ON), DRVI,
and DRVA instructions
Y000 M8343 M8344
If the corresponding rotation
limit relay is turned on,
the
pulse output (operation) will
immediately stop.
If the corresponding rotation
limit relay is turned on, the
speed will decelerate, and
the
operation will stop.
Y001 M8353 M8354
Y002
*1
M8363 M8364
Y003
*2
M8373 M8374
Reverse rotation limit 2
(Servo amplifier side)
Forward rotation limit 2
(Servo amplifier side)
Forward rotation limit 1
(Programmable
controller side)
LSF
Reverse rotation limit 1
(Programmable
controller side)
LSR
Reverse rotation Forward rotation
Servo motor
Forward rotation limit 1
M8343
Forward limit relay for Y000
Reverse rotation limit 1
M8344
Reverse limit relay for Y000