Tower crane rollover protection monitor Presentment tower crane limiters and black box is inability in finding looseness of bolts jointing tower mast and slewing bearing,real time measurement of tower shaft axis laterl verticality,promoting and record of slewing reversion rotation,sudden lowing or release in lifting,inclined hoisting,giving indication for hoisting under wind condition and rollover hidden danger caused by ubiquitous overloading in worksite,which puzzle tower crane user and manager,and use of tower crane rollover protection monitor solves all the problems.