AUTO
CRIB
Appendix II
Explanation of Errors on a RoboCrib
Topic:
Error codes and unwind problems
The RoboCrib model C uses the same basic electromechanical approach to product delivery as previous
models. The system is based on a system of counter rotating platters stacked on multiple levels delivered
to a single aperture or opening. Using this approach the RoboCrib can deliver anyone of up to 2500 bins
or positions to this aperture in less than 7 seconds. This design although very fast and efficient causes
two inherent problems. First in order to drive the large sub platters a serpentine chain is used on the top
of the main platter. This exposes the machine to possible jams in this serpentine chain. Second, the
machine allows the main and large sub platters to rotate in either direction up to 720 degrees. Because the
cables are routed through the down tubes that support the top spider assembly, they will wind up as the
machine rotates. This is not normally a problem as the main controller keeps track of this wind count and
will unwind the machine when it has reached its upper limit of 2 winds in either counter clockwise
direction or the clock wise direction. Only the Main platter and LSP are affected by this problem. In
previous models these problems were dealt with in a number of manual ways.
The development of the model C has a number of significant improvements in dealing with the above
problems. The first improvement is a rotational potentiometer has been mounted both on the LSP platter
and the Main Platter. These potentiometers are electromechanical devices that that have the ability to
read out a specific voltage based on the number of rotations in either the clockwise or counter clockwise
direction. In the rare event that one of the encoders on the MP or LSP are damaged or cease to work, or
power is lost to the controller the machine would lose its wind count stored in volatile memory. On start
up the new controller will read the pot voltage of the potentiometers? Based on the voltage readings the
system would know what the status of machines wind status was from an independent source. This will
virtually eliminate the wind up problems that were inherent in the design of model A and B machines.
The second major improvement comes in the area of Jam protection. In previous models the main
controller had the ability to detect an only 2 types of Jams on a motor. These conditions were as follows a
S1 error would indicate the motor never started moving or a S2 error the motor started turning but
stopped. The model C now has the ability to detect 7 different types of Jams, indicate which platter they
occurred on and attempt to clear the jam and fetch the bin if necessary. Each error code is discussed
below:
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