Mitsubishi Electric MELSEC FX3U Programming Manual page 192

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
2. LDI instruction (initial logical operation, NC contact type)
Circuit program
LDIinstruction
X000
Bus line
Timing chart
X000
ON
Y000
*1
3. Indexing
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.)
Circuit program
X000V0
*1. This function is supported only in FX
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.
Circuit program
D0.3
*1. This function is supported only in FX
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.
190
Y000
ON ON
ON
List program
0000
0003
Y000
3U
List program
0000
0003
Y000
3U
List program
0000 LDI X000
0001 OUT Y000
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
LD X000V0
Z) are converted into octal numbers, and then
OUT Y000
added.
Example:When the value of V0 is 10, LD
/FX PLCs.
3UC
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.
LD D0.3
Specify a bit number as "0, 1, 2, ... 9, A, B, ...
OUT Y000
F" from the least significant bit.
Example:In the example shown on the left, LD
/FX PLCs.
3UC
7 Basic Instruction
Connection to bus line
contact is set to ON (becomes
conductive) or OFF (becomes non-
conductive) by X012.
contact is set to ON (becomes
conductive) or OFF (becomes non-
conductive) by the bit 3 of D0.
7.1 LD, LDI