Mechanical reference point, or mechanical origin, generally has two forms: absolute encoder and stop type. The details are complicated. Take the vertical machining center as an example. Let me say it briefly. \x0d\ If the stroke length of the vertical machining center is: x: 1000mmy: 500mz: 600mm, the stroke of each axis can be found in the parameter 1320, and the soft limit is usually reduced by1-2mm \ x0d \ x0d \ i. Absolute. At the current position, find the parameter 18 15XAPZ and change 1 to 0. \x0d\ 2。 Block-type: \x0d\XY axis is usually based on the center of the workbench. \x0d\ Take the X axis as an example: finding the center of the workbench in the X direction is consistent with the X axis travel in theory, but it is not practical and needs to be adjusted. Moving from this center to the origin of the X axis is the zero point of the X axis. = "Adjust the contacts of the origin stop and the origin induction switch, and observe the X signal of the induction switch at the same time. Once it becomes 1, stop the adjustment. Initially lock the diaphragm, move the X axis, and then return to the original point again. After returning to the origin, use the handwheel to move at the magnification of 10 to detect the contact between the stop of the origin and the induction switch, and the error should be controlled within half a pitch. \ x0d \ x0d \ z axis reference is the distance from the spindle end face to the workbench, which usually depends on the initial setting parameters of the machine tool, generally around 150mm, and then the full upward movement is the z axis origin. The method can be adjusted according to XY. It must be noted that if there is a tool changing device, the change of Z-axis position may affect the accuracy of tool changing, remember. \x0d\\x0d\ Finally, in any case, after adjustment, proofreading should be carried out at the reference position of each axis to prevent deviation from causing collision. \x0d\\x0d\ The following is the information of the net I chose, which is very detailed. If it is not a machine tool manufacturer, it is for reference only. \ x0d \ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = \ x0d \ Keywords: absolute position detection system of reference point relative position detection system \ When replacing or disassembling the motor or encoder, the CNC machine tool will have an alarm message: the absolute position data of the machine in the encoder is lost, or the machine tool finds that the reference point deviates from the position before replacement after returning to the reference point, which requires us to reset the reference point, so it is necessary for us to understand the working principle of the reference point. \x0d\\x0d\ Reference point refers to the point where the machine is located when the G28 instruction of manual reference point regression or machining program is executed, also known as the origin or zero point. Each machine tool has a reference point, and multiple reference points can be set as required for automatic tool change (ATC) and automatic pallet change (APC). The point where G28 instruction performs fast reset is called the first reference point (origin), and the point where G30 instruction performs fast reset is called the second, third or fourth reference point, which is also called the return floating reference point. The point determined by the grid signal or the zero mark signal sent by the encoder is called the electrical origin. The mechanical origin is the reference point of the basic mechanical coordinate system. Once the mechanical parts are assembled, the mechanical reference point is established. In order to make the electrical origin coincide with the mechanical origin, a parameter will be used for setting, and this coincidence point is the origin of the machine tool. \x0d\ The position detection system equipped with machine tools generally includes relative position detection system and absolute position detection system. Because the position data of the relative position detection system will be lost after the machine tool is turned off, it needs to return to zero every time the machine tool is turned on before it can be put into processing operation. Generally, stop zero regression (now machining center) is adopted. The absolute position detection system can detect the movement of the machine tool even when the power supply is cut off, so it is not necessary to return to the original point every time the machine tool is turned on. Because the position data will not be lost after shutdown, and the absolute position detection function can check all kinds of data, such as mutual check of detector feedback, absolute position check of mechanical fixed points, etc., the reliability is high. When the absolute position detector is replaced or lost, the reference point should be set, and the absolute position detection system generally adopts non-stop zero regression. \x0d\ 1: Use the reference point regression mode of the relative position detection system: \x0d\ 1, Fanuc system: \x0d\ 1), and its working principle: \x0d\ When returning to the reference point of the machine tool manually or automatically, the regression axis first moves forward quickly, and when the stopper touches it. When it reaches the zero position relative to the encoder, the regression motor stops and uses this zero position as the reference point of the machine tool. \x0d\2), related parameters: \x0d\ Parameter content system 0i/16i/18i/21i0 \ x0d \ Method for all axes to return to reference points: 0. Stop, 1. No stop, 65438+. How each axis returns to the reference point: 0. Stop, 1. Without stopping,1005.10391\ x0d \ The capacity of each axis reference counter is18210570 ~ 0575707565438. Grid offset of each axis is18500508 ~ 0510645087509 \ x0d \ Whether to use absolute pulse encoder as position detector: 0. No, 1 Yes,186438+05.5566 setting of origin position of absolute pulse encoder: 0. Not true, 1. Established1815.400227022 \ x0d \ Location detection Usage: 0. Built-in pulse encoder, 1. Split encoder, linear ruler 1865438. Fast feed acceleration and deceleration time constant 16200522\x0d\ fast feed speed14200518 ~ 0521\ x0d \ fl speed 14250534\x0d\ Stop of each axis returning to the reference point \x0d\ Mode = 0; Block \x0d\ The reference counter capacity of each axis is set according to the number of feedback pulses per rotation of the motor; \x0d\ Whether to use absolute pulse encoder as position detector = 0; Non \x0d\ absolute pulse encoder origin position setting = 0; \x0d\ Location detection usage type = 0; Built-in pulse encoder \x0d\ fast feed acceleration and deceleration time constant 1620, fast feed speed 1420, FL speed 1425, manual fast feed speed 1424, and servo loop gain 1825 are set according to actual conditions. \x0d\b, restart the machine tool and return to the reference point. \x0d\c Because the reference point of the machine tool is different from that before setting, readjust the grid offset of each axis. \x0d\4), fault example: \ x0d \ 0i-B When the X-axis of the machine tool returns to the reference point manually, the No.90 alarm appears (the position of the returned reference point is abnormal). \x0d\a, the machine tool returns to the reference point and observes the movement of the X-axis. It is found that the X axis does not move fast at first, but the speed is very slow. \x0d\b, detection diagnosis number #300, <128; \x0d\d, check the manual fast-forward parameter 1424 and set it correctly; \x0d\e, check the signals of speed switches ROV 1 and ROV2, and find that the speed switch is broken, and the machine tool is normal after replacement. \x0d\2。 Mitsubishi system: \x0d\ 1) Working principle: \x0d\ After turning on the power supply, the machine returns to the reference point for the first time, and the machine moves quickly. When the test switch of the reference point stops near the reference point, the machine slows down and stops. Then, after stopping at the reference point, the machine slowly moves to the position of the first grid point, which is the reference point. Before returning to the reference point, if the reference point offset parameter is set, the machine will move forward after reaching the first grid point and move to the offset point, taking this point as the reference point. \x0d\2), related parameters: \x0d\ parameter content system M60M64\x0d\ fast feed speed 2025\x0d\ slow feed speed 2026\x0d\ reference point offset 2027\x0d\ grid coverage 2028\x0d\ grid interval 2029 \ x0. Reference point offset = 0 \ x0d \ grid coverage = 0 \ x0d \ grid interval = ball screw fast feed speed, slow feed speed and reference point return direction are set according to actual conditions. \x0d\b, restart the power supply and return to the reference point. \x0d\C, at | alarm/diagnosis |→| servo |→| servo monitoring (2)|, and count the grid interval and grid quantity. \x0d\d, calculate grid coverage: \x0d\ When grid interval /2 grid amount, grid coverage = grid amount+grid interval /2\x0d\e, set the calculated value into the grid coverage parameter. \x0d\f, restart the power supply and return to the reference point again. \x0d\g, repeat the process of c and d, and check whether the grid cover setting value is correct, or reset it. \x0d\h, set the reference point offset as required. \x0d\4)。 Fault example: \x0d\ A Mitsubishi M64 drilling center trips when it returns to the reference point on the Z axis. \x0d\a, check the reference point detection switch signal, which can change from "0" to "1"when moving to the reference point stop position; \x0d\b, check the grid coverage parameters (2028), which is normal; \x0d\ Check the reference point offset parameter (2027), which is normal; \x0d\ Check the regression direction parameter of the reference point (2030) and check it with other machine tools of the same model. It is found that it has changed from "1" in the opposite direction to "0" in the same direction. After correction, restart to the reference point, which is normal. \x0d\3, Siemens system: \x0d\ 1), working principle: \x0d\ When the machine tool returns to the reference point, the return shaft moves quickly to the position of the reference point file block at Vc speed, and when the reference point switch is turned to stop, it starts to slow down and stop, then moves in the opposite direction, exits the reference point stop position, and moves at Vm speed to find the first zero point. Take this point as \x0d\2) and related parameters: \x0d\ parameter content system 802D/8 10D/840D\x0d\ return reference point direction MD340 10\x0d\ switching speed (VC) MD34050\x0d\. Positioning speed (Vp)MD34070\x0d\ reference point offset (Rv)MD34080\x0d\ reference point set position (rk) md34 100 \x0d\ 3. Setting method: \x0d\a, setting parameters: \x0d. \x0d\ When setting the switching speed (Vc) parameter for finding the reference point, it is required that the coordinate axis can stop at the stop point and not cross the stop point when it decelerates to "0"; \x0d\ Reference point offset (Rv) parameter = 0 \ x0d \ b, restart the machine and return to the reference point. \x0d\C, because the reference point of the machine tool is different from that before setting, readjust the reference point offset (Rv) parameter. \x0d\4。 Fault example: \x0d\ A Siemens 8 10D system, the following items should be investigated step by step: \ x0d \ a, poor contact of servo module control signal; \x0d\b, motor and mechanical coupling are loose; \x0d\C, parameter point switch or stop is loose; \x0d\d, the parameter setting is incorrect. \x0d\е, the position encoder power supply voltage is not less than 4.8V；; \x0d\f, the position encoder is faulty; \x0d\g, there is interference in the feedback line of the position encoder; \x0d\ Finally, it was found that the stop loss at the reference point was loose. After tightening the screws, try the machine again and troubleshoot. \x0d\ 2: Absolute position detection system: \x0d\ 1. Fanuc system: \x0d\ 1), working principle: the reference point regression of absolute position detection system is relatively simple. As long as you press any direction key in reference point mode, the control axis will run in the initial setting direction of the reference point gap. After finding the first grid point, \x0d\2), relevant parameters: \x0d\ parameter content system 0i//kloc-. No stop, 65438+. How each axis returns to the reference point: 0. Stop, 1. Without stopping,1005.10391\ x0d \ The capacity of each axis reference counter is18210570 ~ 0575707565438. Grid offset of each axis is18500508 ~ 0510645087509 \ x0d \ Whether to use absolute pulse encoder as position detector: 0. No, 1 Yes,186438+05.5566 setting of origin position of absolute pulse encoder: 0. Not true, 1. Established1815.400227022 \ x0d \ Location detection Usage: 0. Built-in pulse encoder, 1. Split encoder, linear ruler 1865438. Fast feed acceleration and deceleration time constant 16200522\x0d\ fast feed speed14200518 ~ 0521\ x0d \ fl speed 14250534\x0d\ Servo loop gain 182505 17\x0d\ returns to the initial direction of reference point gap 0. Positive 1. Negative 1006000370030066\x0d\3), setting method: \x0d\a, setting parameters: \. \x0d\ Mode of returning reference points for each axis = 0; \x0d\ The reference counter capacity of each axis is set according to the number of feedback pulses per revolution of the motor; \x0d\ Whether to use absolute pulse encoder as position detector = 0; \x0d\ Absolute pulse encoder origin position setting = 0; \x0d\ Location detection usage type = 0; \x0d\ Fast feed acceleration and deceleration time constant, fast feed speed, FL speed, manual fast feed speed and servo loop gain are set according to actual conditions; \x0d\b, restart the machine tool and manually return to the vicinity of the reference point; \x0d\c, whether to use absolute pulse encoder as position detector =1; \x0d\ Setting of origin position of absolute pulse encoder =1; \x0d\e, restart the machine tool; \x0d\f Because the reference point of the machine tool is different from that before setting, readjust the grid offset of each axis. \x0d\2。 Mitsubishi system (taking M60 and M64 as examples): \x0d\ 1), non-stop mechanical bump mode: \x0d\a, setting parameter: # 2049. = 1 No stopping in mechanical bump mode; \x0d\#2054 Current limit; \x0d\b, select "Absolute Position Setting" screen, and select handwheel or inching mode (automatic initialization mode can also be selected); \x0d\C, in the "Absolute Position Settings" screen, select "Touchable Pressure"; \x0d\d, #0 absolute position setting = 1, #2 origin setting: set coordinate values of reference points according to basic mechanical coordinates; \x0d\e, move the control shaft. When the control shaft touches the mechanical brake and reaches the limit current within a given time, the control shaft stops and moves in the opposite direction. If the handwheel or inching mode is selected in step b, the control shaft moves in the opposite direction to the first grid point, which is the electrical reference point; If the "automatic initialization" mode is selected in step b, the #2005 impact velocity parameter and #2056 approach point value should be set in step a. At this time, the control shaft moves reversely to the value of #2056 (approaching point) and then moves to the stop position of #2055 (impact speed) to reach the limit current within a given time. \x0d\g, restart the power supply. \x0d\2)。 Adjustment reference point without stopping: \ x0d \ a. Setting parameter: # 2049 = 2. Adjust the reference point without stopping the machine; \ x0d \ # 2050 = 0 positive direction, = 1 negative direction; \x0d\b, select "Absolute Position Setting" screen, and select handwheel or inching mode; \x0d\c, in the "Absolute Position Settings" screen, select the "No Touch Pressure" mode; \x0d\d, #0 absolute position setting = 1, #2 origin setting: set coordinate values of reference points according to basic mechanical coordinates; \x0d\e, move the control axis near the reference point. \x0d\f, # 1 = 1, the control axis moves in the setting direction of #2050, and stops when it reaches the first grid point, which is set as the electrical reference point. \x0d\g, restart the power supply. \x0d\3。 Siemens system (such as 802D, 8 10D, 840D): \x0d\ 1), debugging; \ x0d \ a. Setting parameters: \x0d\MD34200=0. Absolute encoder position setting; \x0d\MD342 10=0。 Initial state of absolute encoder; \x0d\b, select "Manual" mode and move the control shaft to the vicinity of the reference point; \x0d\c, input parameter: MD34 100, coordinate position of machine tool; \x0d\d, activate the adjustment function of absolute encoder: md34210 =1=1. Absolute encoder adjustment state; \x0d\e, press the machine tool reset key to make the machine tool parameters take effect; \x0d\f, the machine tool returns to the reference point; \x0d\g, the machine tool does not move, and the system automatically sets the parameter: 34090. Reference point offset; 342 10. The absolute encoder has been set, and the position displayed on the screen is the setting position of MD34 100. \x0d\2), related parameters: \x0d\ parameter content system 802D.8 10D.840D\x0d\ parameter point offset 34090\x0d\ machine tool coordinate position 34 100\x0d\ absolute encoder position setting 34200. 0. Initial 1. Adjustment 2. Setup completed 342 10 \ x0d \ x0d \ In the reference point regression of the relative position detection system, after the first reference point regression of the machine tool, when the G28 instruction of manual reference point regression or machining program is executed, the machine tool does not slow down and move to the reference point stop position, but continues to locate to the reference point stored in the memory at high speed. When downloading the PCL program, the position of the reference point will be lost. After PCL debugging is completed, the reference point regression setting of absolute encoder will be debugged.