External data record selection
227
11.1.2 External data record selection
Application:
One of eight various workpieces should be made available at a data collection station. The number of the
desired workpiece is set using a BCD selector switch. The transportation process is then triggered by a
starting pulse.
Assignments:
station
7
removal
station
station
6
station
5
station
4
station
3
station
2
station
1
station
0
+960
+840
+720
+600
+480
+360
+240
+120
0 -60
workpiece pick-up
The horizontal movement is implemented using an NC axis controlled by COMPAX. A pneumatic cylinder,
which is controlled by COMPAX using a double solenoid valve, raises and lowers the workpiece pick-up.
COMPAX performs all the functions required without superordinate control.
Wiring up the digital inputs and outputs:
I1
I2
I5
I6
I10
I11
I12
I13
O7
O8
I9
I14
I15
I16
search MZ
start
stop
BCD-switch
I7
I8
pick-up lifted
pick-up lowered
lower
pick-up
lift
pick-up
evaluation by
external calling
of command lines
removal
station empty
1
2
4
BCD
+24V
+24V
+24V
COMPAX
+24V
Comments:
♦
The inputs I9, I14, I15 and I16 have to be placed on GND or left open.
♦
The BCD switch has eight settings. The outputs are encoded with binary.
♦
The "Data collection station empty" switch is closed when the data collection station is closed. The switch
operation prevents the workpiece pick-up being lowered for as long as there is a workpiece in the data
collection station.
Function:
The first event after COMPAX has been started is the approaching of the data collection station. If the
workpiece pick-up is not lowered, the assumption is made that there is still a workpiece in the workpiece
pick-up. This is deposited in the data collection station by lowering the workpiece pick-up. The system is now
ready for the first transportation process.
