It is now possible to accurately control Print and Varnish unit trips directly from an Allen-Bradley
or Siemens PLC
Control Technology has developed several high speed logic subroutines that operate on Allen-Bradley's ControlLogix 5561 or Siemens' Simantic 319 processors. This enables high speed control of the Rutherford print carriage and varnish unit trip functions from within the PLC. Previously this control was handled outside the PLC using a Systems Engineering or Hyde Park black box solution.
New 3 Mandrel Trip Feature!
CTI has also implemented a new feature not available with pervious Rutherford deocrator control packages. It is called a 3 Mandrel Trip Option. With a conventional control system at speeds much above 1500 CPM (40 ms. between mandrels), the Print Carriage Trip Timing Window and Solenoid Extend./Retract times must be set very accurately to insure on a trip that the skipped mandrel is not inadvertently partially printed. If any of these parameters are not precisely set, the plant air pressure changes or the mechanical movement time of the carriage changes due to lubrication or adjustment, the electrical system can't automatically correct for these conditions.
With the new 3 Mandrel Trip Option, instead of tripping out on just one mandrel, we trip out around 3 mandrels. This makes the machine setup less critical and insures no printed mandrels. If the timing drifts, the ink will go on one of the two silver cans surrounding the missing can, not on the bare mandrel. No more ink on mandrels which can be transferred to the inside of subsequent cans.
In the single mandrel trip option, one mandrel will be skipped and 2 cans will be blown off at the pin chain. In the 3 mandrel trip option 3 mandrels will be skipped and 4 cans will be blown off at the pin chain.
The conventional single mandrel trip option is still available. The operational mode is selected through the HMI.
