Mitsubishi Electric MELSEC FX Series - Important Memory Locations

Learning to Use the FX Family for Positioning Control MELSEC FX PLC positioning
4 - 4
MITSUBISHI ELECTRIC
4.1.2 Important memory locations
For FX PLC programs using positioning instructions, there are several built-in special devices to define
control parameters and facilitate system operation. These devices consist of 1-bit, 16-bit, and 32-bit
address locations and are briefly outlined below according to their use in the example programs in the
following section. Use this table as a reference to understand the example programs. For details on
other memory addresses (for example, operation information for control on Y001 or Y002), refer to the
FX
3S /FX 3G /FX 3GC /FX 3U /FX 3UC Series User’s Manual - Positioning Control Edition (JY997D16801).
Function name Device Length Description Applicable PLC
RUN monitor M8000 1-bit ON when PLC is in RUN. FX
1S , FX 1N , FX 3G ,
FX
3GC , FX 3GE , FX 3S ,
FX
3U(C)
Initial pulse M8002 1-bit ON for the first scan only.
Instruction execution
complete flag
M8029 1-bit Programmed immediately after a positioning
instruction. Turns ON when the preceding instruc-
tion finishes its operation and stays ON until the
instruction stops being driven.
CLEAR signal output
enable
M8140 1-bit Enables a CLEAR signal to be output to the servo. FX
1S , FX 1N
Pulse output stop com-
mand
M8145 1-bit Stop outputting Y000 pulses. (Immediate stop) FX 1S , FX 1N
M8349 FX 3G , FX 3GC , FX 3GE ,
FX
3S , FX 3U(C)
Pulse output monitor
flag
M8147 1-bit OFF when Y000 is READY
ON when Y000 is BUSY
FX 1S , FX 1N
M8340 FX 3G , FX 3GC , FX 3GE ,
FX
3S , FX 3U(C)
Instruction execution
abnormally complete
flag
M8329 1-bit Programmed immediately after a positioning
instruction. Turns ON when an instruction fails to
complete correctly and stays ON until the instruc-
tion stops being driven.
FX
3G , FX 3GC , FX 3GE ,
FX
3S , FX 3U(C)
CLEAR signal output
function enable
M8341 1-bit Enables an output to be used for the CLEAR signal
for Y000.
FX 3G , FX 3GC , FX 3GE ,
FX
3S , FX 3U(C)
(Y000) Zero return
direction specification
M8342 1-bit OFF  Reverse rotation
ON  Forward rotation
Forward rotation limit M8343 1-bit Forward pulses on Y000 stop when this relay turns
ON.
Reverse rotation limit M8344 1-bit Reverse pulses on Y000 stop when this relay turns
ON.
(Y000) Positioning
instruction activation
M8348 1-bit OFF when a positioning instruction is not active.
ON when a positioning instruction is active.
CLEAR signal device
specification function
enable
M8464 1-bit Enables the output terminal for the CLEAR signal to
be changed for Y000.
Bias speed [Hz] D8145 16-bit Sets the bias speed for Y000. FX
1S , FX 1N
D8342 FX 3G , FX 3GC , FX 3GE ,
FX
3S , FX 3U(C)
Maximum speed [Hz] D8146 32-bit Sets the maximum speed for positioning instruc-
tions on Y000.
FX 1S , FX 1N
D8343 FX 3G , FX 3GC , FX 3GE ,
FX
3S , FX 3U(C)
Acceleration/decelera-
tion time [ms]
D8148 16-bit Sets the acceleration and deceleration time. FX 1S , FX 1N
Acceleration time [ms] D8348 16-bit Sets the acceleration time for Y000. FX 3G , FX 3GC , FX 3GE ,
FX
3S , FX 3U(C)
Deceleration time [ms] D8349 16-bit Sets the deceleration time for Y000.
CLEAR signal device
specification
D8464 16-bit Sets the output terminal for the CLEAR signal for
Y000.
Tab. 4-4: Special devices of FX 1S , FX 1N , FX 3G(C)(E) , FX 3S and FX 3U(C) base units