回参考点故障（Reference return fault）.docVIP

回参考点故障（Reference return fault） Reference point for NC machine according to the different detection element absolute pulse coder and incremental pulse encoder two, using absolute pulse coder as feedback element, in the machine installation, the normal use of the process, as long as the absolute pulse encoding for backup battery effectively, since each boot, neednt return to the reference point of operation. The system uses incremental pulse encoder in the machine after each boot must first return to the reference point of the operation, to determine the origin of the machine tool, and the main reference point for zero switch, zero encoder or grating pulse, there are two general ways. 1) fast moving axial pre designated direction, the block pressure zero switch deceleration forward movement, until the block from zero after the switch control system began to look for zero, when receiving the first zero pulse, then determine the reference point position. FANUC system and Beijing KND system of machine tools are currently using this kind of zero return mode. 2) fast axis according to predetermined direction, block to zero pressure switch, reverse deceleration, and from zero when the switch shaft, change direction, move to the direction of the reference point, when the block again under the pressure of zero switch, CNC system began to look for zero, when receiving the first zero pulse. Then determine the reference point position. SIEMENS, the United States AB system and the central China system of machine tools generally use this zero return mode. The way how the movement system is decided by setting machine parameters of PLC programming and CNC system, motion speed of the shaft is set in the machine parameters in the process of NC machine tool return reference point is PLC system and CNC system with the completion of the NC system is given by zero order, and shaft the movement in a predetermined direction, the pressure switch to zero (or zero off switch), PLC issued a dec