Filter
Top Products
13 Applied Instructions (Handy Instruction)
13.1 IST / Initial State
318
FXCPU Structured Programming Manual
[Basic & Applied Instruction]
4. Special auxiliary relays for IST command(M)
Auxiliary relays (M) used in IST command are divided into those controlled automatically by the command
depending on the circumstances, and others that must be controlled by the program depending on the
operation preparation or purpose of control.
1) Those controlled automatically by IST command
a) M8040: Transfer ban
When this auxiliary relay is put in action, transfer of all states is banned.
individual : Always M8040 is active.
Return home, one-cycle: When stop button is pressed, the operation is held until start button is
pressed.
Stepping : Always M8040 is active. However, only when start button is pressed, the
operation is stopped, and is transferred.
Other : Operation is held when PLC is changed from STOP to RUN, and is
canceled when start button is pressed.
In transfer ban state, the output in the state continues to operate.
b) M8041: Transfer start
This is the auxiliary relay required as transfer condition from initial state S2 to next state.
Individual, return home : Not active.
Stepping, one-cycle : Active only while start button is pressed.
Continuous : Operation is held when start button is pressed, and canceled when stop
button is pressed.
c) M8042: Start pulse
Active momentarily only when start button is pressed.
d) M8047: STL monitor valid
M8047 is turned ON when IST command is used.
STL monitor is valid when M8047 is ON, and active state numbers (S0 to S899) are stored in the
special data register D8040 to D8047 in numerical order.
As a result, up to eight operation state numbers can be monitored.
If any one of these states is active, the special auxiliary relay M8046 operates.
2) Those driven by sequence program
→ For detail of these controls, see next page.
a) M8043: Return home end
In the return home mode, when the machine reaches the home position, operate this special auxiliary
relay (M) from the user side program.
b) M8044: Home position condition
You can drive this special auxiliary relay by detecting the home position condition of the machine. The
signal is valid in all modes.
c) M8045: All output reset ban
When the modes are changed over in individual, return home, and automatic modes, unless the
machine is at home position, all outputs and operation states are reset. However, when the M8045 is
driven, only the operation states are reset.