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FX3S/FX3G/FX3GC/FX3U/FX3UC Series
Programming Manual - Basic & Applied Instruction Edition
7 Basic Instruction
7.1 LD, LDI
2. LDI instruction (initial logical operation, NC contact type)
3. Indexing
*1
Devices used in LD and LDI instructions allow indexing with index registers (V and Z).
(State relays (S), special auxiliary relays (M), 32-bit counters (C), and "D.b" cannot be indexed.)
V0 to V7 and Z0 to Z7 are available in indexing.
When used devices are inputs (X) and outputs
(Y), values of index registers (V and Z) are
converted into octal numbers, and then added.
Example: When the value of V0 is 10, LD contact
is set to ON (becomes conductive) or
OFF (becomes non-conductive) by
X012.
*1. This function is supported only in FX
3U
/FX3UC PLCs.
4. Bit specification of data register (D)
A bit in data register (D) can be specified as a device used in LD and LDI instructions.
When specifying a bit in data register, input "."
after a data register (D) number, and then input a
bit number (0 to F) consecutively.
Only 16-bit data registers are available.
Specify a bit number as "0, 1, 2, ... 9, A, B, ... F"
from the least significant bit.
Example: In the example shown on the left, LD
contact is set to ON (becomes
conductive) or OFF (becomes non-
conductive) by bit 3 of D0.
*1. This function is supported only in FX
3U
/FX3UC PLCs.
Errors
• When an I/O number used in LD or LDI instruction does not exist due to indexing, M8316 (Non-existing I/O
specification error) turns ON.
• When the device number of a device (M, T or C) other than I/O used in LD or LDI instruction does not exist due to
indexing, an operation error (error code: 6706) occurs.
X000
Y000
LDI instruction
Circuit program List program
LDI
OUT
0000
0001
X000
Y000
Connection to bus line
ONON
ONON
X000
Y000
Timing chart
Bus line
X000V0
Y000
Circuit program List program
LD
OUT
0000
0003
X000V0
Y000
D0.3
Y000
Circuit program List program
LD
OUT
0000
0003
D0.3
Y000