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7 Absolute Position Detection System (Absolute Current Value Read)-ABS
7.1 Instruction Format
B - 107
FX
3G
/FX
3U
/FX
3UC
PLC User's Manual - Positioning Control Edition
Built-in Positioning Functions
A
Common Items
B
Built-in
Positioning
Functions
Apx.
Example
Connection
7. Absolute Position Detection System
(Absolute Current Value Read)-ABS Instruction
With the use of the servo absolute position detection system, the built-in positioning function uses the current
ABS value read-out (ABS) instruction to read out the current value (absolute position (ABS) data) from the
MELSERVO-H, -J2(S), or -J3 servo amplifier.
→ For items to be observed in programming, refer to Section 4.7.
→ For the servo amplifier and connection of the MELSERVO Series, refer to the Appendix and the
examples of connection.
7.1 Instruction Format
1. Instruction Format
2. Data setting
3. Devices
1 : D.b is available only in FX3U and FX3UC PLCs. However, index modifiers (V and Z) are not available.
2 : Only available for to FX
3U and FX3UC PLCs.
Operand type Description Data type
Specifies the first number of the device that inputs the absolute position (ABS) data
from the servo amplifier. Number of occupied points: 3 (first point for )
BIN16-bit
Specifies the first number of the device that outputs the absolute position (ABS) data
control signal to the servo amplifier. Number of occupied points: 3 (first point for )
Specifies the absolute position (ABS) data (32-bit value) storage device number. BIN32-bit
Operand
type
Bit device Word device Others
System user Digit designation System user
Special
unit
Index
Con-
stant
Real
num-
ber
Char-
acter
string
Pointer
XYMTCSD.b KnX KnY KnM KnS T C D R U/G VZ
Modify
KH E ""P
333 3
1
3
33 3
1
3
3 3 3 3333
2
33 3
FNC 155
ABS
ABSOLUTE
D
DABS
−
32-bit
instruction
Instruction
symbol
Execution condition
13 steps
Continuous
execution
type
−
−
16-bit
instruction
Instruction
symbol
Execution condition
Command
input
FNC 155
DABS
S
•
D
1
•
D
2
•
S
S
D
1
D
1
D
2
S
D
1
D
2