Zero Pressure Accumulation

A power conveyor where product is accumulated and the conveyable surface stops driving the product.  Sensors detect when the product gets to a certain predetermined zone and then the drive is disengaged and product stops until such time as the PLC releases it.  The stopped zone communicates with the zone directly behind it that it is full and any additional product will have to be accumulated behind it.  This occurs in a daisy chain manner where each zone communicates directly with the zone behind it.  When product is released from leading zone, it communicates with zone directly behind it that it can now accept product and so on, on down the line.