Computer controlling apparatus for portal jib crane

The utility model relates to a computer controlling apparatus for a portal jib crane, mainly comprising a programmable controller, a variable frequency speed regulator, an optical rotary encoder, an intermediate relay, a grab bucket linkage table and a cart and a carriage linkage table; the control technology and the position sensing technology of the programmable controller are used for using programs to replace a relay-a contactor control; the speed control method of an AC motor uses variable frequency speed control; so the automation control of a portal jib crane is realized. The utility model has the advantages of reliable operation, long service life of equipment, hard false operation, low failure rate and little maintenance.