Dry Processing Technology
www.foodengineeringmag.com/articles/91673-vacuum-conveyor-timers

Vacuum conveyor timers
December 11, 2013
Volkmann electronic timers for the electro-pneumatic operation of its Multijector VS and PPC series vacuum conveyors come in basic ET3 and ET4 models; they control the conveyors using a small PLC controller. Both timers can interface with the user’s PLC and level probes. The ET4 version also is capable of controlling a line clearing valve.