The maintenance method of Siemens CNC system failure

If the monitor light blinks at 1Hz, the EPROM is faulty. If the flickering frequency is 2Hz, the plc is faulty. If it flashes at a frequency of 4Hz, it will keep the battery alarm, indicating that the voltage is insufficient. Indicates that the interface board 03731 of the operation panel is faulty or the CRT is faulty.

1) There is no basic screen display after the power is turned on

(a) There is no monitor light display on the circuit board No. 03840
(b) No. 03840 The monitoring light on the circuit board is on
①The monitoring light is flickering. If the monitoring light flickers at 1Hz, the EPROM is faulty; if the flickering frequency is 2Hz, the PLC is faulty; if it flickers at 4Hz, the battery will keep alarming, indicating that the voltage is insufficient.
②The monitor lights are off on the left and on on the right. Indicates that the interface board 03731 of the operation panel is faulty or the CRT is faulty.
③The monitoring light is always on. The usual reasons for this kind of failure are: CPU failure; EPROM failure; system bus (ie backplane) failure, incorrect settings on the circuit board, wrong machine data, and circuit boards (such as memory boards, coupling boards, measurement board) hardware is faulty.

2) CRT displays confusion

(a) The voltage of the battery (lithium battery) is too low. At this time, alarm No. 711 can be displayed.
(b) Storage area clutter due to power strip or storage being unplugged. This is a kind of soft fault, as long as the CNC internal program is cleared and re-entered, the fault can be eliminated.
(c) A hardware failure on the power board or memory board causes the program display to be confused.
(d) If No. 513 alarm is displayed on the CRT, it means that the capacity of the memory is not enough.

3) The program cannot be started in the automatic mode

(a) At this time, alarm No. 351 is generated, indicating that after the CNC system is started, the machine tool has not returned to the reference point operation.
(b) The system is in automatic hold state.
(c) Disable cycle start. Check the interface signal Q64.3 between PLC and NC.

4) Feed axis movement failure

(a) The feed axis cannot move. The reasons for this failure are:
①The operation mode is wrong;
②The signal transmitted from PLC to NC is not normal;
④ Alarm No. 22 occurs, which means that the position loop is not ready.
⑤The measuring system is faulty. For example, No. 108, 118, 128, and 138 alarms are generated, which is caused by the measurement sensor being too dirty. If 104, 114, 124, 134 alarms are generated, the position loop has a hardware failure.
⑥The motion axis is in the state of software limit. It can be released by moving the machine axis in the opposite direction.
⑦ When alarms 101, 111, 121, and 131 occur, it means that the machine tool is in a mechanical clamping state.
(b) The motion of the feed axis is discontinuous.
(c) The feed shaft vibrates.
① The speed loop and current loop parameters of the feed drive unit are not optimized, or the AC motor is out of phase or the speed measuring element is damaged, which can cause the feed shaft to vibrate.
②The position control board of the CNC system is faulty.
③The friction force of the mechanism is too large.
④ CNC machine tool data is wrong, the correct setting of machine tool data is as follows.
(d) The feed axis is out of control.
①If there are 101, 111, 121, 131 alarms, please check the clamping.
② If there are 102, 112, 122, 132 alarms, it means that the command value is too high.
③The feed drive unit is faulty.
④ CNC machine tool data setting is wrong, causing the position control loop to be positive feedback.
⑤ The polarity of the command line output from the CNC device to the drive unit is wrong.
(e) No. 103-133 alarm. This is a profile monitoring alarm. The speed loop parameters are not optimized or the KV coefficient is too large.
(f) No. 105-135 alarms. Caused by too much position drift. If the displacement exceeds 500mv, check the drift compensation parameters N230~N233.

5) Spindle failure

If the actual spindle speed exceeds the maximum speed of the selected gear, alarm No. 225 will be generated; if the spindle position loop monitoring fails, then Alarm No. 224 occurred.
6) V·24 serial interface alarm
(a) When no data is sent or received within 20 seconds:
① external device failure;
② cable Incorrect;
③The 03840 board is faulty.
(b) The perforated paper tape information cannot be input, the reasons are as follows:
① The key switch on the operation panel is in the off position, so that the paper tape program cannot be input;
② If the data on the 0384 board When the protection switch is not in the release position, the data tape cannot be input;
③ If the subroutines L80~L99 and L900~L999 cannot be input, it may be caused by the PLC and NC interface signal Q64·3 being “1” (circulation prohibited).
(c) Stop bit error.
①The baud rate setting is wrong;
②The reader is faulty;
③The machine data is wrong.