Mitsubishi Electric WS0-CPU0 - Start Warning

Chapter 9
182
Logic programming – Function blocks
9.8.14 Start warning
Function block diagram
General description
Many machines must be equipped with a start warning mechanism, e.g. if the
machine operator can not see all dangerous areas from one location because of the
size of the machine.
After a start button has been pressed, the waiting time starts and a warning signal is
initiated. After expiration of the waiting time the release time starts and a second
warning signal is initiated. During the release time it is possible to start the machine by
pressing the start button a second time.
The start warning is required for automatic run mode as well as for the safe inch mode
of the machine.
Start sequence
1. On startup the function block is in Inactive mode. The Startup active output is High
while all other outputs are Low.
2. If the Control input becomes Low and the Lock and Stop inputs are High, the start
sequence is enabled and the function block goes into Waiting for start mode.
3. A rising edge on the Inch forward or on the Inch backward input will trigger the
start sequence:
– The Startup active output changes to Low, the waiting time and the signal time
start and the Waiting time active output as well as the Warning output change
to High for the duration of the signal time.
– After expiration of the Waiting time the Release time and the Impulse time
start. The Waiting time active output changes back to Low, the Release time
active output changes to High and the Warning output changes to High again
for the duration of the impulse time.
4. If during the release time a second rising edge of Inch forward occurs, the function
block will transit to inch mode (Forward) and the Enable and Forward active
outputs will change to High. Respectively, if during the release time an additional
rising edge of Inch backward occurs, the function block will transit to inch mode
(Backward), and the Enable and the Backward active outputs will change to High.
Figure 170:
Function block diagram for
the Start warning function
block
Note