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PLC User's Manual - Positioning Control Edition
Built-in Positioning Functions
6 Mechanical Zero Return (DSZR/ZRN Instruction)
6.2 DOG Search Zero Return (DSZR Instruction)
B - 95
A
Common Items
B
Built-in
Positioning
Functions
Apx.
Example
Connection
1. Zero return operation
Zero return operation is described below assuming that Y000 is specified as the pulse output destination
device . If Y001, Y002, or Y003 is specified, it is necessary to change the output number of each related
relay (special auxiliary relay, special data register) below.
→ For details on related relays, refer to Section 4.1 to Section 4.4, or Subsection 6.2.2.
1) Specify the zero return direction.
Turn the "zero return direction specification" relay (M8342) on or off to specify the zero return direction.
2) Execute the DSZR instruction to perform zero return.
3) Transfer operation will be performed in the direction specified by the "zero return direction designation"
flag (M8342) at the speed specified by the "zero return speed designation" device (D8347, D8346).
4) If the near-point signal (DOG) specified by is turned on
*1
, the speed will be reduced to the creep
speed (D8345).
5) After turning the near-point signal (DOG) OFF
*1
, if the zero-phase signal specified by is
turned on
*2
, the pulse outputting operation will immediately stop.
If the same input is specified for both the near-point signal and the zero-phase signal, turning the near-
point signal (DOG) OFF
*1
will immediately stop the pulse outputting operation (just like the ZRN
instruction where the zero-phase signal is not used).
6) If the CLEAR signal output function (M8341) is enabled (set to ON), the CLEAR signal (Y004) will be
turned on within 1 ms after stopping the pulse outputting operation, and will be kept ON for "20 ms + 1
scan time (ms)".
7) The current value register (D8341, D8340) will be reset to "0" (will be cleared).
8) The "Instruction execution complete" flag (M8029) will turn on, and the zero return operation will be
completed.
→ For details on the "Instruction execution complete" flag, refer to Subsection 4.7.4.
*1. This step is described assuming that the "DOG signal logic reverse" relay (M8345) is off. If this flag is
on, it is necessary to change the expression "on" to "off", and "off" to "on".
*2. This step is described assuming that the "Zero point signal logic reverse" relay (M8346) is off. If this
flag is on, it is necessary to change the expression "on" to "off", and "off" to "on".
D
1
S
1
S
1
S
2
Maximum speed
(D8344,D8343)
Zero return speed
(D8347,D8346)
Deceleration
time
(D8349)
Bias speed
(D8342)
Acceleration
time
(D8348)
DOG
Creep speed
(D8345)
CLEAR signal
(Y004)
Zero-phase signal
S
2
•
S
1
•
Current value register = "0"
Zero return
direction
M8342=OFF
(D8341,D8340)
ON
"Instruction
execution
complete"
flag M8029
Front endRear end
1 ms or less
20 ms + 1 scan time (ms)
When the instruction is turned off, M8029 is turned off.