ch = channel number (1-8)
fn_num = Custom Function # to trigger when value is reached.
value = trigger when HSC reach this (32-bit) integer value.

If the PLC supports quadrature encoder inputs, then the HSC counter variable HSCPV[ch] will increment/decrement according to direction of rotation. When value is reached, the specified custom function activates immediately.

Important : All High Speed Counters are disabled automatically when the PLC is reset unless they are enabled by the HSCDEF statement. However, if more than one HSCDEF for the same channel ch is executed, only the last executed HSCDEF statement will take effect. Hence you should put the next HSCDEF statement within the CusFn triggered by the first HSCDEF. By chaining the HSCDEF statement from one CusFn to another, you can control the motion of the machine using the HSC value to execute a series of CusFn one by one. Within these CusFn you can program what to do to control the motion. E.g. changing the speed, putting on the brake, change direction of motion, etc. You can use the SETBIT, CLRBIT for digital ON/OFF control and setDAC, setPWM for proportional control.