Fatek PLC fbs 20 ma

[mechatron]

Dear all. Please help me, i am working on fbs 20 ma PLC made by fatek. it uses the programming software Winproladder. The i have to write is to output 1khz signal to a dc motor, to measure rpm of motor a Hall sensor is used, for each rotation it sends the pulse to plc. the logical work i have to do is to keep the rpm of motor constant. Please help me,in making this program logical