a lower frame and an external frame connected to said lower frame, and said lower frame having a loading side and an operator side;

a lift mechanism coupled to said lower frame and said external frame, and said lift mechanism comprising a lift frame and a lift operatively coupled to said lift frame and an upper drive mechanism, said lift being configured to raise and lower said lift frame between an elevated position and a lowered position, said upper drive mechanism being coupled to said external frame and operatively coupled to said lift frame and configured to move said lift frame in the elevated position between said loading side and said operator side;

said loading side being configured with a load side sensor, and said operator side being configured with an operator side sensor;

a controller, said controller having an input/output module, said input/output module being operatively coupled to said load side sensor and to said operator side sensor;

a first carriage for carrying a first bin, said first carriage being operatively coupled to said lift frame and operatively coupled to said lift mechanism and said lift mechanism being further configured to move said first carriage between said lowered position and said elevated position at said loading side and at said operator side under the control of said controller;

a second carriage for carrying a second bin, said second carriage being operatively coupled to said lower frame and operatively coupled to a lower drive mechanism configured to move said second carriage between said loading side and said operator side under the control of said controller;

said external frame including a loading side position sensor and an operator side position sensor operatively coupled to said controller, said loading side position sensor being configured to detect when said first carriage or said second carriage is positioned in a loading/unloading position at the loading side, and said operator side position sensor being configured to detect when said first carriage or said second carriage is positioned in a loading/unloading position at the operator side;

said controller being configured to operate said lift mechanism in a bypass mode, said bypass mode comprising moving said lift frame and said first carriage in the elevated position above the lower frame between said loading side and said operator side;

said controller being further configured to operate said lower drive mechanism to move said second carriage between said loading side and said operator side when said first carriage is in the elevated position when said lift frame and said first carriage are in said elevated position;

said controller being configured to be responsive to an input from said load side sensor indicating a breach condition, and in response to the occurrence of a breach condition during any movement of said first carriage, any movement of said second carriage or any movement of said lift mechanism, said controller being configured to generate a cycle-stop state; and

said controller being configured to be responsive to an input from said operator side sensor indicating a breach condition, and in response to the occurrence of a breach condition during any movement of said first carriage, any movement of said second carriage or any movement of said lift mechanism, said controller being configured to generate a cycle-stop state.