Mitsubishi Electric MELSEC FX3U Programming Manual page 188

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
Limitation in simultaneous instances of instructions
Some applied instructions can be programmed two or more times, but the number of simultaneous instances
is limited.
Even in instructions not shown below, if two or more instructions are driven at the same time for a same I/O
number, it is regarded as double outputs. In some combinations of instructions, the operation may be
disrupted, or the instructions cannot be executed.
For details, refer to the caution described in each instruction page.
For combinations of instructions, refer to "6.4 Mutual relationship among program flow control instructions".
1. Positioning instructions
Do not drive FNC 57 (PLSY), FNC 58 (PWM), FNC 59 (PLSR), FNC150 (DSZR), FNC151 (DVIT), FNC156
(ZRN), FNC157 (PLSV), FNC158 (DRVI) and FNC159 (DRVA) instructions at the same time for the same
output number.
2. High speed processing instructions
• FX /FX
3U 3UC
In FNC 53 (HSCS), FNC 54 (HSCR) and FNC 55 (HSZ) instructions (including FNC280 (HSCT)
instruction), make sure that up to 32 instructions are driven at the same time. [FNC280 (HSCT) instruction
can be used only once.]
Note that "FNC280 (HSCT) instruction", "table high speed comparison mode of FNC 55 (HSZ) instruction)"
and "frequency control mode of FNC 55 (HSZ) instruction" can each only be used once.
• FX PLC
3G
The FNC53 (HSCS), FNC54 (HSCR) and FNC55 (HSZ) instructions can be driven up to 6 times in total at
the same time.
3. External device communication instructions
• In FNC 80 (RS) and FNC 87 (RS2) instructions, do not drive two or more instructions at the same time for
the same port.
• It is impossible to combine and use FNC 80 (RS), FNC 87 (RS2), FNC270 (IVCK), FNC271 (IVDR),
FNC272 (IVRD), FNC273 (IVWR) and FNC274 (IVBWR) instructions for the same port.
• In FNC270 (IVCK), FNC271 (IVDR), FNC272 (IVRD), FNC273 (IVWR), FNC274 (IVBWR), FNC300
(FLCRT), FNC301 (FLDEL), FNC302 (FLWR), FNC303 (FLRD), FNC304 (FLCMD) and FNC305
(FLSTRD) instructions, two or more instructions can be driven at the same time for the same port.
186
PLC
6 What to Understand before Programming
6.5 General Rules for Applied Instructions