Patent ID: 8401814

Claim:
A limit switch for use with a hoist system that lowers and lifts a load, the hoist system including a hoist motor controlled by a variable frequency motor drive and an electronic sensor that generates an indicator signal corresponding to one or more rotations of a component on the hoist system, the limit switch comprising: a first input for receiving the indicator signal; memory locations for storing top and bottom stop limit values associated with respective top and bottom stop limit locations on the hoist system; a software module programmed to determine a current location value from the indicator signal, to compare the current location value with the top and bottom stop limit values, and to utilize the comparison between the current location with the top and bottom stop limit values to stop the lowering or lifting of the load at or near the stop limit locations; a processor for executing the software module; and wherein the memory locations, the software module and the processor are components of and embedded in the variable frequency motor drive used by the hoist system.