Theory of Operations
Rovema VPK Operators Manual
3/2000 VPK REV(B) PANELVIEW 600
4-2
Forming Cycle
The forming cycle is based on a 360 degree virtual encoder count
(resolver count). During one revolution of the horizontal sealing jaws,
all of the forming operations occur once. Most of the operations start
and stop at a specific degrees of rotation. When the encoder count is
between a forming operations on/off cam values, the motion controller
signals the PLC to activate that operation.
The vertical sealing device engage/retract movements and the product
dump request are forming operations that do not rely on the encoder
count. The vertical sealing device engages the film tube a few
milliseconds before the film feeding device starts advancing film and
retracts from the film tube a few milliseconds after film feeding stops.
The product dump request is sent a few milliseconds before the
horizontal sealing jaws close.
