FANUC-BESK 7M CNC 05# 07# and 37# alarms
Fault phenomenon: Y-axis speed is abnormal, 05#, 07# and 37# alarms.
Fault inspection and analysis: Check the FANUC-BESK 7M system maintenance manual, 05# system emergency stop signal is connected; 07# is the speed control unit alarm; 37# is the Y-axis position control offset is too large.
From the maintenance manual, 05# alarm is caused by emergency stop, and it is not difficult to eliminate its alarm. For 07# alarm, the maintenance manual points out: the speed control unit of any axis is in an alarm condition, or the contactor of the motor power line is disconnected, which generates this alarm. The following reasons can be considered: ① Motor overload; ② Speed control power transformer overheating; ③ Speed control power transformer power fuse broken; ④ On the control part power input terminal board, the contact between EMGI N1 and EMGI N2 of the terminal block Xl is open; ⑤ On the control part power input bracket, the AC 100V fuse (F5) is broken; ⑥ The signal cable connecting the speed control unit and the control part is disconnected or falls off from the contact; ⑦ For some reason, other servo mechanisms alarm and the contactor (MCC) on the motor power line is disconnected.
After macro analysis of the above 7 items, we believe that 07# alarm and 05# are caused by the abnormal speed of the Y axis, and we use emergency stop measures. Therefore, the focus of the inspection is on 37# alarm.
From the maintenance manual, there are two reasons for 37# alarm: ① The servo motor power line is broken; ② The connection between the position detector and the servo motor is loose.
Analyze the reason ①, the servo motor has a speed, indicating that the power line is not broken. At the same time, we adjusted the offset compensation in the position control loop to the CRT display and compared it with the normal value, and there was no abnormality. Thus, the problem of excessive Y-axis position offset was ruled out. For ②, we used the segmented judgment method to conduct a detailed inspection of the 01 GN 710 position controller of the NC system according to the maintenance principle of "first outside and then inside". The specific steps are as follows: ① According to the characteristics that the structures and parameters of the three servo drive systems of X, Y, and Z are completely consistent, the connection lines XC (Z axis) and XF (Y axis) of the position controller in the NC of the two servo drive systems of Y and Z are swapped, that is, in the machine tool control, the Z axis is controlled by the Y axis signal, and the Y axis is controlled by the Z axis signal, to check the quality of the NC system. After the swap, the fault still exists, indicating that the NC system is fault-free; ② Swap the Y and Z servo drive systems in the standard electric cabinet, that is, use the Z axis control signal to drive the Y axis, and the fault still exists, and the problem of the servo drive system is ruled out, and the fault range is narrowed to the Y axis DC servo motor. After disassembling the DC servo motor, it was found that the connecting gear between the tachometer generator and the servo motor was loose. Since the tachometer generator is a component that generates acceleration or deceleration signals and controls the rotating machinery at a constant speed in the automatic control system. Therefore, the loose connection between it and the servo motor will cause inaccurate constant speed control, and even generate acceleration signals to the CNC, resulting in abnormal Y-axis speed.
Solution: Tighten the connecting gear and troubleshoot |
