Mitsubishi Electric MELSEC FX3U Programming Manual page 408

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
1. Control of devices by switch operations (occupied devices)
While the command input is ON, the following devices are automatically switched and controlled. While
the command input is OFF, the devices are not switched.
Device number
M8040
M8041
M8042
M8043
M8045
M8047
*1.Cleared when the PLC mode is changed from RUN to STOP.
*2.Set to ON when END instruction is executed.
Do not program the following state relays as general state relays;
Device number
S0 to S9
S10 to S19
If the devices are switched among individual operation (X020), zero return (X021) and automatic
operation (X022, X023 and X024) while the zero return complete device (M8043) is OFF, all outputs are
set to OFF.
Automatic operation can be started again after zero return is completed.
→ For introducing IST instruction, refer to "14.1.2 Example of IST instruction introduction
Cautions
1. Device specified as
It is not necessary to use all switches for mode selection.
When some switches are not used, leave the corresponding numbers in the unused status. Such numbers
cannot be used for any other purpose.
2. Programming order of IST instruction and STL instruction
• IST instruction should be programmed earlier than a series of STL circuit such as state relays S0 to S2.
3. State relays used for the zero return operation
Use the state relays S10 to S19 for the zero return operation.
In the final state in the zero return operation, set M8043 to ON, and then let it be reset to OFF by itself.
4. Limitation in the number of IST instruction
IST instruction can be used only once in a program.
406
Operation function
STL transfer disable
*1
Transfer start
Start pulse
*1
Zero return complete
All output reset disable
*2
Enable STL monitoring
Occupied for the initial state
• S0 to S2 are used for individual operation, zero return and automatic operation as shown above.
• S3 to S9 can be used arbitrarily.
Occupied for zero return
D
S
1 and switches to be used
14 Handy Instruction – FNC 60 to FNC 69
14.1 FNC 60 – IST / Initial State
Device number
S0 Individual operation initial state
S1 Zero return initial state
S2 Automatic operation initial state
Operation function
(example of workpiece transfer mechanism)".
Operation function