Parker Products COMPAX-M /-S (L) manual Mark-referenced positioning

Mark-referenced positioning

11.1.3 Mark-referenced positioning

Application:

Pieces with lengths of between 100 mm and 500 mm should be cut from a plate roller. The cut-off positions are specified by marks on the plate. If two marks are separated by more than 500 mm, the plate should be pulled back to the last cut-off position.

Assignments:

light

barrier

label

shears

label window: range within which labels are detected

POSR	POSR
50mm	50mm
A	P38 = +650
P37 = +50	P39 = +680
initial position	B
P37: minimum distance to label.	A : position if label
P38: maximum distance to label.	appears at 50mm.
P39: maximum feed if no label appears	B : position if label
within the window.	appears at 650mm.

The plate is fed by a roller feed controlled by COMPAX. A reflex light barrier detects the marks on the plate and reports this to COMPAX. The distance between the light barrier and the shears is 50 mm. The shears are controlled and monitored by COMPAX.

Wiring up the digital inputs and outputs:

start			shears	0	= block
		COMPAX O7		1	= activate
+24V	I5
stop			shears	0	= block	shears
	I6	I7		1	= open
	O16	O14
0 = label detected	I15	I14	label input	0	= no label	light
massage 1 = label missing	O15	I16		1 = label
						barrier

Function:

The first event after COMPAX has been started is a rest of the control outputs. Once assurance has been received that the blades of the shears are open, COMPAX is ready for the initial cutting to length.

The cutting to length process is triggered by a start pulse. COMPAX firstly activates the mark reference (I14) using O14. After a waiting time of 10 ms (which is used to compensate for any possible COMPAX timing offset), the mark-referenced positioning process is started using the "POSR 50 mm" command. The mark input (I16) is approved after a travel distance of 50 mm (P37). If the light barrier now detects a mark, COMPAX pushes the plate another 50 mm. This distance corresponds to the distance between the light barrier and the shears and is programmed using "POSR 50 mm". If no mark has been detected after a travel distance of 650 mm (P38), COMPAX stops the feed movement after a total of 680 mm (P39).

At the end of the positioning process, output O16 indicates whether a mark has been detected within the mark window or not. This output is queried using I15.

If I15 is at 1 (i.e. mark found), COMPAX sets the message output O15 to 0 and activates the shears. Once the blades have opened, COMPAX waits for the next start pulse. If I15 is 0 (i.e. no mark found), COMPAX sets the message output O15 to 1, blocks the mark reference (I14) via O14, pulls the plate back by 680 mm to the last cut-off position and waits for the next start pulse.

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