LINK Systems System 2500 PLS - Manual (Page 51)

System 2500 Operating & Installation Manual - Revision 07 2-43
Figure 12
A Track input is used to
monitor an air cylinder
Figure 13
Transfer mode timing
2.9.3 TRACK
Tracking inputs are used to monitor events that should closely follow (track) a System 2500 PLS
output. A die protection input can be programmed to track a PLS output within a specified
period of time. When programming an input for Track Mode the operator will first be asked to
enter the PLS channel to be tracked and
then the tracking time (the amount of time
that the die protection input is allowed to
'lag' behind the PLS output). The tracking
time can range from 4 ms to 999 ms in 1
ms increments.
An example of the use of a tracking input
is monitoring an air cylinder used for
parts ejection as shown in Figure 12.
Suppose a PLS output on the System 2500
is used to activate the cylinder. A switch
is set to close when the air cylinder is not
extended (at the home position). Should
the air cylinder jam in the extended
position, the switch will not close when
the output turns off. The die protection
will detect a fault and stop the press
before the dies can close on the cylinder.
Notice in the above example that the output turning on activated the air cylinder, which in turn
opened (turned off) the switch. For the switch to track the PLS output, the input to the die
protection must be inverted. When programming an input for track mode, the operator is asked if
he wishes to invert the input or not.
2.9.4 TRANSFER
Transfer inputs are used to monitor automatic transfer
mechanisms. Some progressive dies cut the part away from the
stock at an early stage in the die. Automatic transfer
mechanisms are then used to move the separate pieces to the
next stage in the die. Each gripper on the transfer mechanism
should have a switch to detect that each part is in place in the
transfer mechanism. These switches can be attached to transfer
mode inputs to monitor the mechanism for dropped parts during
the transfer.