Mitsubishi cnc boot parameters settings and alarm release - Database & Sql Blog Articles

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After the Mitsubishi CNC hardware connection check and setup is completed and the system is powered on, the "READY" green light on the display remains off. Moreover, a lot of alarm contents are displayed on the [Diagnostics]-[Alarm] screen, which makes the debugging engineer who used Mitsubishi CNC for the first time confused. And Mitsubishi CNC has more than 700 parameters, which ones must be set when booting? How to solve the fault alarm? This article explains the above problems based on the debugging experience, in order to help the commissioning engineer.

1. Boot parameters

1.1 Basic parameter settings

The original system displays Japanese after booting. For easy operation, set parameter #1043=22 (Simplified Chinese) first. (Some systems such as C64 do not have Simplified Chinese specifications, then set #1043=15 Traditional Chinese).

Setting #1138=1 (selecting the parameter with the parameter number) means entering the parameter number and the screen immediately switches to the parameter screen.

The following are the parameters that must be set after booting:

#1001 - Whether the setting is a single system or a dual system and the presence or absence of a plc axis.

#1002——Set the number of axes of the NC axis and PLC axis.

#1013 - Set the name of each axis.

#1037——G code system and compensation type

(milling machine: #1037=2, lathe #1037=3)

(This parameter must be set before executing #1060 formatting)

#1060 - This parameter is especially important. Its function is "execute the initialization of system startup"

The function has 2: one is to initialize the parameters according to the set value of #1001——-#1043. The significance is that the number of NC axes and the number of spindles have been set in #1001——-#1043. After #1060 is set, the parameters of each servo axis and spindle are automatically displayed on the screen. Otherwise, the parameters of each servo axis and spindle are not called up.

The second is to format the machining program and tool compensation data. And enter the standard canned cycle.

After setting the #1001——-#1043 parameter accurately, you must set #1060 as prompted. #1155=100 #1156=100

The fixed signal address specified by the Mitsubishi NC system is as follows:

1-axis origin X18 1 axis + limit X28 1 axis - limit X20

2-axis origin X19 2 axis + limit X29 2 axis - limit X21

3-axis origin X1A 3-axis + limit X2A 3-axis - limit X22

4-axis origin X1B 4-axis + limit X2B 4-axis - limit X23

If the input signal address occupied by the home switch and the limit switch is different from the system specification, it must be changed by setting parameters.

#2073——Set the origin signal address

#2074-Set the positive limit signal address

#2075-Set negative limit signal address

BIT5=1 of #1226 (make the above settings valid)

1.2 Servo motor parameter setting:

#2219-(Location encoder resolution)

#2220=――(Speed ​​encoder resolution)

#2225=―-(Motor model)

#2236-(The connected regenerative braking resistor or power unit model)

1.3 Parameters related to the spindle

The following parameters must be set when the system is equipped with a spindle:

#1039-(Set the system with several spindles);

#3024-(Set the connected spindle type

#3024=1.Bus connection is the servo spindle)

#3024=2 Analog output is the inverter spindle)

#3237=0004 (PLG is valid)

#3238=0004 #3025=2 (Encoder feedback series communication is valid. Display the actual spindle speed)

#3239——Spindle servo drive type

#3240——Spindle motor type

#3241——Type of brake unit or brake resistor connected

1.4 PLC parameters #p#page title#e#

#6449=00000011——The counter in the PLC program, the timer is valid.

#6450=00000101 - The alarm information and operation information take effect.

#6451=00110000——PLC program communication is valid.

Mitsubishi NC has up to 700 parameters, which are not required and cannot be set at boot time. The above parameters must be set after power on.

2. Common fault alarms and elimination after power on

After the power is turned on, many fault alarms may be displayed on the [Diagnostics]-[Alarm] screen, and some alarms are not the same as the actual ones, and need to be analyzed and judged to be released.

2.1 [M01 0006 XYZ] - This fault alarm indicates that one axis or three axes all exceed the hard limit.

Phenomenon: The actual situation is that each axis has not moved and does not touch the limit switch.

Fault analysis and troubleshooting:

A. The limit switch signal address is connected according to the system, but it is connected to the normally open point, and the system detects the overtravel fault.

Disposal: Simply connect the limit switch to the normally closed point and the fault is eliminated.

B. The limit switch signal addresses are not connected as specified by the system.

Disposal: Set parameters #2073, #2074, #2075, #1226 to connect the limit switch signal to the normally closed point.

2.2

[S02 2219 XYZ] ,

[S02 2220 XYZ] ,

[S02 2225 XYZ],

[S02 2236 XYZ] - The initial parameter setting is incorrect.

Disposal: This means that the servo parameters set after power on are incorrect, and should be set according to the motor or encoder model.

2.3 [Y03 MCP XYZ] - Servo drive is not installed

Phenomenon: The actual situation is that the servo drive is installed. Why is this type of alarm?

Analysis and disposal:

1. Each connecting cable is not plugged in. Remove each cable and re-tighten it.

2. If a cable is faulty, replace the cable.

3. The power-on sequence is incorrect. The servo system should be powered first, and finally the controller should be powered.

4. The axis number of the drive is set correctly. Or the terminal plug is not connected.

2.4 [Z55-RI/O not connected]

Phenomenon: The actual situation is that the system is not equipped with RI/O at all. In another case, the system is indeed equipped with RI/O and the connection is completed. But why is there such an alarm?

Analysis: ● The power-on sequence is incorrect. The controller is powered up and then the RIO is powered up. As a result, the controller does not detect RIO.

●. The main cable CF10 (controller - basic I/O) is not properly connected.

Disposal:

1. Change the power-on sequence.

2. Re-insert the CF10 cable.

3. Check the power supply to the RI/O.

2.5 [EMG LINE] - Emergency stop failure due to improper connection

Analysis: It may be that the failure of a connection cable may also be a connection failure.

Disposal: Re-insert and retighten each cable. Or replace the SH21 cable with R000

cable. Generally, there are 10 wires in the SH21 cable, but the R000 cable must be used for the C1 driver. The R000 cable must be full of 20 wires.

2.6 [EMG SRV] - Emergency stop due to servo system failure

analysis:

1. The SH21 cable disconnection may cause the fault. This fault may also occur when the SH21 cable is poorly connected.

2. The fault will also occur if the power-on sequence is incorrect.

Disposal: Replace the SH21 cable and power it up in the normal order.

2.7 [ EMG PLC] - Emergency stop caused by PLC program #p#Page title#e#

Disposal: Monitor the cause of Y29F=ON caused by the PLC program and cancel the fault that caused the emergency stop.

2.8 [EMG STOP] - The PLC program is not running.

Disposal: 1. Check if the "NCSYS" knob behind the controller is =1"

Set this knob to "0"

2. Set PLC = "RUN" on the display.

3. After executing “Format PLC Memory” on the communication screen of GX-D software, re-incoming the PLC program.

2.9[U01——-No user PLC] - PLC program has not been entered yet

Disposal: Enter the PLC program.

Example 301. The machine tool violently shakes and the drive displays AL-04 alarm

Fault phenomenon: A vertical machining center equipped with FANUC 6 system, during the machining process, the machine tool is violently shaken, and the AC spindle drive displays AL-04 alarm.
Analysis and processing: FANUC AC spindle drive system AL-04 alarm means "P1, F2, F3 fuse blown in the AC input circuit", the possible causes of the fault are:
1) The output impedance of the AC power supply is too high.
2) The inverter transistor module is defective.
3) Defective rectifier diode (or thyristor) module.
4) The surge absorber or capacitor is defective.
Check the cause of the above failures one by one. Check the AC input power. In the input power of the AC spindle drive, the R and S phase input voltage is 220V, but the T phase AC input voltage is only 120V, indicating that there is a problem with the driver's three-phase input power.
Further check the three-phase output of the spindle transformer, and find that the transformer input and output, the machine power input are equally unbalanced, indicating that the cause of the fault is not in the machine itself.
Check the three-phase fuse on the switchgear of the shop and find that the impedance of one phase is hundreds of ohms. After disassembling and checking, it was found that the fuse wiring screw was loose, which caused the three-phase input power to be unbalanced; after reconnection, the machine tool returned to normal.

Example 302. Faulty repair of the alarm "A"

Fault phenomenon: A CNC lathe supporting FANUC 0T, after starting up, the system is in the “Emergency Stop” state, “NOTREADY” is displayed, and the spindle alarm indicator on the operation panel is on.
Analysis and processing: According to the fault phenomenon, check the machine AC spindle drive and find that the drive is displayed as “A”.
According to the alarm display of the drive, as mentioned in the previous chapter, the meaning of the drive alarm is “driver software error”. This alarm is more likely to occur when the drive is subject to external accidental interference. The solution is usually to initialize the drive. In this machine, the parameters are initialized as follows:
1) Turn off the power of the driver and set the set terminal S1 to TEST.
2) Turn on the power to the drive.
3) Press and hold MODE, UP, DOWN, DATASET 4 keys at the same time
4) When the display changes from full dark to "FFFFF", release all the keys and keep them for more than 1 s.
5) Press and hold the MODE and UP buttons simultaneously to display the FC-22 parameter.
6) Press and hold the DATASET button for more than 1 s. The display shows “GOOD” and the standard parameters are written.
7) Turn off the power to the drive and reset S1 (SH) to "DRIVE".
Through the above operations, the drive returns to normal, the alarm disappears, and the machine returns to normal operation.

Example 303. Faulty repair of overcurrent alarm in the drive

Fault phenomenon: A horizontal machining center equipped with FANUC 11M system, the spindle runs suddenly during machining, and the drive displays an overcurrent alarm.
Analysis and processing: After checking the main circuit of the AC spindle drive, it was found that the regenerative braking circuit and the fuse of the main circuit were all blown, and the machine tool returned to normal after replacement. However, after the machine has been in normal operation for several days, the same fault occurs again.
Due to the repeated occurrence of the fault, it proves that there is a problem with the spindle system of the machine tool. According to the alarm phenomenon, the main reasons for the analysis may be:
1) Defective spindle drive control board.
2) The motor is continuously overloaded.
3) There is a local short circuit in the motor windings.
In the above points, the cause of the motor overload can be eliminated according to the actual machining conditions on site. Considering that the driver can work normally for several days after replacing the components, the possibility of the spindle driver control board being defective is also small. Therefore, the most likely cause of the failure is a partial short circuit in the motor winding.
Carefully measure the phase resistance of the motor windings during maintenance and find that the insulation resistance of U is relatively small, which proves that there is a local short circuit to ground.
When the motor was disassembled, it was found that the insulation sleeve at the connection between the internal winding of the motor and the lead wire had aged; after reconnection, the resistance to ground returned to normal.
After replacing the components again, the machine tool returns to normal and the fault no longer occurs.

Example 304. Repair of the spindle drive AL-12 alarm

Fault phenomenon: A horizontal machining center equipped with FANUC 11M system, the spindle running suddenly stops during the machining process, and the drive displays the No. 12 alarm.
Analysis and processing: The meaning of the No. 12 alarm in the AC spindle drive is “DC bus overcurrent”. As mentioned in the previous chapter, the possible causes of the fault are as follows:
1) A partial short circuit at the motor output or motor winding.
2) The inverter power transistor is defective.
3) The drive control board is faulty.
According to the above reasons, the maintenance was carefully checked. Make sure there is no local short circuit at the motor output and motor. Then disconnect the drive (machine) power supply and check the inverter transistor assembly. Remove the motor armature wire by opening the drive, and check the collector (C1, C2) and emitter (E1, E2), the base (B1, B2), and the base (B1) of the inverter transistor assembly with a multimeter. The resistance between B2) and the emitter (El, E2) is compared with the normal value (shown in Table 7-25). It is found that a short circuit between C1-E1, that is, the transistor component has been damaged.

Table 7-25 Normal resistance value of inverter transistor component Measurement terminal Multimeter measurement method Normal value Measurement end Multimeter measurement method Normal value
CE positive terminal C several hundred ohms CB negative terminal C ∞
Negative termination C ∞ BE positive termination B a few hundred ohms
CB positive terminal C several hundred ohms negative terminal B ∞

To determine the cause of the fault, the transistor drive circuit on the drive control board was further examined. The check method is as follows: #p#Page title#e#
1) Remove the DC bus fuse F7, close the AC power supply, and input the rotation command.
2) According to the pins of Table 7-26 and Table 7-27, the control voltage between the base B and the emitter E of 8 transistors (model Etl91) is measured through the connection sockets CN6 and CN7 of the driver, and according to CN6 The corresponding relationship between the CN7 pin and each transistor pin is checked one by one (to the extreme reference of the emission, the normal value of the measured BE is generally about 2V). The inspection found that the voltage between 1C and lB was 0V, which proved that the C~B pole broke down and found that the diode D27 was also broken down.
Table 7-26 Pins of CN6
1 2 3 4 5 6 7 8 9 10 11 12
5C 5B 5E 6C 6B 6E 7C 7B 7E 8C 8B 8E

Table 7-27 Pins of CN7
1 2 3 4 5 6 7 8 9 10 11 12
1C 1B 1E 2C 2B 2E 3C 3B 3E 4C 4B 4E

After replacing the above components, start the spindle drive again and display the alarm as AL-19. As mentioned earlier in this chapter, the driver AL-19 alarm is an overcurrent alarm for the U-phase current detection circuit.
In order to further check the cause of the AL-19 alarm, the power supply to the control loop was checked during maintenance.
Check the driver power test terminal, the AC input power is normal; the DC output +24V, +15V, +5V are normal, but the -15V voltage is "0". Further check the power supply circuit and found that the integrated regulator (model: 7915) is damaged. After replacing the 7915, the -15V output voltage is normal, the spindle AL-19 alarm is eliminated, and the machine tool returns to normal.

Example 305. Repair of the spindle drive AL-01 alarm

Fault phenomenon: A vertical machining center equipped with FANUC 21 system, during the machining process, the spindle runs suddenly, the system displays ALM2001, ALM4 09 alarm, AC spindle drive shows AL-01 alarm.
Analysis and processing: The system of the machine is FANUC 21 system. The alarms displayed on the CRT are as follows:
ALM2001: SPDL SERVOAL (spindle drive alarm).
ALM409: SERVO ALARM (SERIAC ERR).
Spindle drive AL-01: Spindle motor overheat alarm.
The above alarm can be cleared by the reset button. After the system is cleared, the system can start. There is no alarm on the spindle. However, after the manual reference point return action of each axis is normally executed, the above alarm occurs when the Z axis moves downward.
When the actual machine tool alarm occurs, only the Z axis moves downward, the spindle motor does not rotate and does not generate heat. Considering that the spindle motor moves up and down along with the Z axis, it can be roughly determined that the failure is due to the Z axis movement, causing the spindle motor cable to bend and causing poor contact.
Open the spindle motor terminal box and find that the spindle motor thermistor wiring on the plug in the junction box is loose. After reconnection, the fault is removed and the machine tool returns to normal.

Example 306. Faulty maintenance of abnormal vibration of the spindle at high speed

Fault phenomenon: A CNC lathe with FANUC 0TA2 system has abnormal vibration when the spindle rotates at high speed (above 3000r/min).
Analysis and processing: The vibration of CNC machine tools is related to the design, installation, adjustment of the mechanical system, the natural frequency of the mechanical system, and the natural frequency of the spindle drive system. The reasons are usually complicated.
However, on this machine, since the AC spindle drive system works normally before the fault, it can rotate at high speed; and when the spindle exceeds 3000r/min, the vibration exists at any speed, and the cause of mechanical resonance can be eliminated.
Check the installation and connection of the mechanical transmission system of the machine tool. No abnormalities were found. After disconnecting the spindle motor from the machine tool spindle, the spindle speed and torque display were observed from the control panel, and the value was found to have a large change. The fault is determined in the electrical part of the spindle drive system.
After carefully checking the spindle drive system connection of the machine tool, it was found that the grounding wire of the spindle drive of the machine was poorly connected. After the ground wire was reconnected, the machine tool returned to normal.

Example 307. Faulty repair of the spindle sound and overcurrent alarm

Fault phenomenon: A CNC copying machine equipped with FIDIA l2 system and FANUC l5 DC spindle drive. After the spindle is started, the sound is dull during operation; when the spindle is braked, the CRT displays “FEED HOLD”, the spindle drive device The "Overcurrent" alarm indicator lights up.
Analysis and processing: In order to determine the cause of the spindle overcurrent alarm, the connection between the spindle motor and the spindle was first disengaged during maintenance, and the mechanical transmission system was inspected. No abnormality was found, thus eliminating the mechanical cause.
Then measured and checked the winding of the motor, the resistance to the ground and the connection of the motor. When the commutator and the brush were inspected, it was found that some of the brushes had reached the limit of use, and the surface of the commutator had serious burning marks. .
In response to the above problems, the same type of brush was first replaced during maintenance; the motor was disassembled, and the surface of the commutator was repaired to complete the maintenance of the motor.
After re-installing the motor and then testing, the fault disappeared; but when the machine was turned on the next day, the above fault occurred again, and the fault disappeared automatically after the machine was powered on for about 30 minutes.
According to the above phenomenon, since the mechanical transmission system, the spindle motor, and the connection are excluded, it is possible to determine the cause of the failure on the spindle driver.
According to the schematic diagram of the spindle servo drive system, the relevant lines of the current feedback link are analyzed and inspected. The parts of the circuit board that may be soldered are re-welded, and all the connectors are surface-treated, but the fault phenomenon Still unchanged.
Since there is no drive spare part at the repair site, it is impossible to exchange the circuit board of the drive. In order to determine the approximate part of the fault, the fault can be automatically disappeared after the machine is energized for about 30 minutes, and the local warming method is adopted during maintenance. Through the hair dryer at 8~10cm away from the circuit board, each part of the circuit board was locally warmed up. It was found that when the trigger circuit was warmed up, the spindle operation could resume normal immediately. From this analysis, it is preliminarily determined that the fault location is on the trigger line of the driver.
Observing the output waveform of the trigger part of the line through the oscilloscope, it is found that one of the integrated circuits has no trigger pulse generated at normal temperature, causing the trigger pulse of the four thyristors (two of the positive group and the reverse group) of the U phase of the rectifier circuit to disappear: replace this Troubleshooting after the chip.
After the repair is completed, the cause of the fault is further analyzed. When the spindle drive is working, the three-phase full-control bridge rectifies the main circuit, and there is a phase without a trigger pulse, which causes the DC bus rectified voltage waveform to become larger, the harmonic component is increased, and the motor commutation is difficult. The motor is running dull.
When the spindle is braked, since the drive uses feedback braking, the control circuit first turns off the positive group of trigger pulses and triggers the reverse group of thyristors to invert them. In the case of inverter, the lack of one-phase trigger pulse also makes the energy not be fed back to the grid in time. Therefore, the motor generates overcurrent, and the driver generates an overcurrent alarm to protect the circuit.

Example 308~ Example 311. Spindle only drift speed repair

Example 308. Fault phenomenon: A CNC milling machine equipped with FANUC 7 system, the spindle can not reach the command speed under the automatic or manual operation mode, only 1~2r/min, the positive and negative conditions are the same, and the system has no alarm.
Analysis and processing: Since the machine has the spindle shifting function, in order to verify the mechanical transmission system operation, the high and low shifting operation tests were carried out in the MDI mode during maintenance, and the machine tool was found to be normal, indicating the shifting mechanism of the mechanical transmission system. Normal, the cause of gear meshing is ruled out.
Check that the cable connection of the spindle drive and the status indicator on the spindle drive are in normal working condition, and it can be preliminarily determined that the spindle drive is working properly.
Further measurement of the spindle drive command voltage input VCMD, found that under any S command, VCMD is always "0", that is, the drive has no speed command input.
Check the CNC control cabinet and find that the plug XN of the spindle analog output on the position control board is loose; after reinstallation, the machine tool returns to normal.

Example 309. Fault phenomenon: An imported horizontal machining center equipped with FANUC ll system, the S command is invalid, the spindle speed is only 1~2r/min, and there is no alarm.
Analysis and processing: Measure the speed command PcMD signal of the spindle drive and find that under any S command of O-4500r/min, VCMD is always 0, further measure the S analog output of CNC, and its value is also “0”, indicating The CNC's spindle speed control command is not output.
Since the CNC has no alarm display, the spindle speed control command is not output. The possible cause is that the spindle does not meet the conditions of the speed output. According to the interface signal of the system, through the analysis of the ladder diagram of the PLC program, it is found that the flag of the high/low speed shift of the spindle in the PLC program and the input signal of the high/low speed shift detection switch of the machine tool are all “0”, which is related to the actual situation. Does not match.
By manually controlling the solenoid valve, after the machine is switched to the low gear, the input signal of the low speed gear detection switch of the machine tool is correct, and the flag of the low speed gear shift of the spindle in the PLC becomes the correct state, which satisfies the spindle condition. The spindle is started again under this condition and the machine returns to normal.
In order to further determine the cause of the machine tool failure, after executing M42 (high-speed command) by MDI mode, it is found that the M42 command cannot be completed. Check that the high-speed solenoid valve has been energized, but the high-speed gear in-position signal is “0”, thereby determining the cause of the fault in the mechanical or hydraulic part of the machine.
Check the inside of the headstock and find that the shifting fork of the machine's shifting mechanism is loose. In the low speed gear, the fork can be lowered by the self-weight due to the downward movement of the fork, so the machine can work normally; when shifting the high gear, the fork moves upwards and pulls The gear cannot be inserted after the exit. After reinstallation, the machine returns to normal.

Example 310. Fault phenomenon: A used CNC milling machine equipped with FANUC 0M adopts FANUC S series spindle drive. After starting up, no matter the input S**M03 or S**M04 command, the spindle only rotates at low speed, and the actual speed cannot reach the command value.
Analysis and processing: On the CNC machine tool, the spindle speed control is generally based on the different S codes of the CNC system to output different spindle speed analog values, and the spindle shifting is realized by the spindle drive.
On this machine, check that the spindle drive has no alarm and the spindle has a low speed rotation. It is basically confirmed that the spindle drive is not faulty.
According to the fault phenomenon, in order to determine the fault location, the spindle analog output of the measuring system is measured by the multimeter, and it is found that the value changes under different S** commands, thereby confirming that the numerical control system works normally.
Analyze the control characteristics of the spindle drive. In addition to the analog input, the spindle rotation requires a given direction of rotation as the most basic input signal.
Under the premise of confirming that the analog input of the spindle drive is correct, the spindle steering signal is further checked, and the polarity of the input analog quantity is inconsistent with the steering input signal of the spindle; after the analog polarity is exchanged, the power is turned on again, the fault is eliminated, and the spindle can rotate normally. .

Example 311. Fault phenomenon: A used CNC lathe with FANUC 0T adopts FANUC S series spindle drive. After starting up, no matter the input S**M03 or S**M04 command, the spindle only rotates at low speed, and the speed cannot reach the command value.
Analysis and processing: Since the spindle drive has no alarm display, the fault analysis process is the same as the above example. On this machine, the input of the analog input of the spindle and the input of the spindle steering signal are correct, thus eliminating the possibility of system failure, the polarity of the spindle input analog quantity and the steering input signal of the spindle.
Considering that the machine tool is a used machine tool, the factory default parameters of the spindle of the machine tool have been lost. The parameters have been initialized before the spindle is commissioned. Therefore, the spindle drive parameters are not properly set. #p#分页头#e#
Check the spindle parameters according to the actual connection of the spindle drive. It is found that the driver in the spindle does not use the external "spindle override" to adjust the potentiometer. The spindle drive parameter is set to the external "spindle override", so the spindle speed is multiplied. It is fixed at "0", causing the above failure.
After the parameters are modified, the spindle work returns to normal and the fault is eliminated.

Example 312. Fault repair that the spindle cannot rotate

Fault phenomenon: A horizontal machining center equipped with FANUC 6M system, in manual and automatic mode, the spindle does not rotate, the drive and CNC have no alarm display.
Analysis and processing: Using the MDI method, execute the S100M03 command, the system "Cycle Start" indicator lights up, check the NC diagnostic parameters, and find that the system has output S code and SF signal normally, indicating that the NC works normally.
Check the PLC program and check the spindle start condition and the status of the internal signal. The spindle start condition is satisfied. Further checking the signal input of the spindle drive has also met the conditions for normal operation. It is therefore possible to confirm the fault in the spindle drive itself.
According to the measurement of the spindle driver and the signal state of the detection terminal, the voltage and waveform of the signal are checked one by one. Finally, the driver D/A converter has a digital signal input, but its output voltage is “0”.
After the D/A converter integrated circuit chip (chip model: DAC80-0B1) was unplugged, it was found that one of the pins had broken: after the repair, the machine tool returned to normal.

Example 313. Fault repair caused by the spindle caused by the block cannot continue

Trouble phenomenon: When a horizontal machining center equipped with FANUC 6 system is used for automatic machining, after the program is executed to the M03S**** block, the spindle can be started and the rotation speed is correct, but the next block cannot be executed. The drive does not have any alarms.
Analysis and processing: On-site inspection, the machine manually inputs M03 or M04 command in MDI mode, the spindle can rotate normally, but the S command value is modified, the new S command cannot take effect; and the M05 command stops the spindle or presses the reset button. After clearing, any speed command can be executed.
Check the machine diagnostic parameter DGN700.0=1, indicating that the machine is executing M, S, T functions; further check the PLC program ladder diagram, find that the spindle forward rotation signal SFR or spindle reverse rotation signal SRV can be "1", namely: M command The output has been normal, but the S function completion signal SFIN (diagnostic number DGN208.3) is 0, causing the machine to wait.
Continue to check the ladder diagram and find that the condition of the machine tool SFIN=1 is: S function strobe signal SF (diagnostic number DGN66.2) is "1", spindle speed arrival signal SAR (diagnostic number DGN35.7) is "1" ", the spindle shift completion signal SPE (diagnostic number DGN208.1) is "1". The actual state is SF=1, SAR=0, SPE=0, so SFIN=0. From the system manual, SF, SPE, and SFlN are internal signals from CNC to PLC. SAR is related to external conditions.
Checking the SAR signal input finds that the driver "spindle speed arrival" signal output is high when the fault occurs, but the corresponding SAR signal on the numerical control system I/O board is low.
Check the signal connection and find that there is a wire break in the cable. After reconnecting, the machine tool returns to normal.

Example 314. The machine cannot complete the "shift" fault repair

Fault phenomenon: A CNC lathe with FANUC 0TA2 system, when the machine executes the spindle drive stage exchange command M41/42, the spindle is always in the jitter state, and the “shift” action cannot be completed.
Analysis and processing: According to the fault phenomenon, it is easy to determine that the fault is caused by the inability of the spindle drive stage exchange command M41/42 to be completed.
Checking the solenoid valve signal and the hydraulic cylinder action, it is found that the shifting action has actually been completed, but the slip gear shifting in-position signal is still "0" because the non-contact switch for detecting is defective.
After replacing the non-contact switch, the machine returns to normal.

Example 315. Trouble repair in thread processing

Fault phenomenon: A CNC lathe with a matching Ossen R2J50L system has a fault in the initial section of the thread when the G32 is threaded.
Analysis and processing: CNC lathe machining thread, which is essentially the interpolation between the angular displacement of the spindle and the Z-axis feed. The “disorganized tooth” is caused by the synchronization between the spindle and the Z-axis feed.
Since the machine uses the frequency converter as the spindle speed control device, the spindle speed is open-loop control. Under different loads, the starting time of the spindle is different, and the spindle speed at start-up is unstable, and the speed also changes accordingly. The spindle and Z-axis feed cannot be synchronized.
There are two ways to solve the above faults:
1) By adding the G04 delay command before the spindle rotation command (M03) and before the thread machining command (G32), it is ensured that the thread machining is started after the spindle speed is stabilized.
2) Change the starting point of the thread machining program to make it away from the workpiece for a certain distance, to ensure that after the spindle speed is stable, then the workpiece is actually contacted and the thread machining is started.
By using any of the above methods, the fault can be solved and normal threading can be realized.

Example 316. Fault repair on the surface with periodic vibration

Fault phenomenon: A CNC lathe with FANUC OT-A2 system has found periodic ripples on the surface during machining.
Analysis and processing: When machining the end face of CNC lathe, there are many reasons for the occurrence of vibration on the surface. In mechanical aspects such as poor installation of components such as cutters, lead screws and spindles, and insufficient precision of the machine tool, the above problems may occur.
However, the machine tool appears periodically and has a certain regularity. According to the normal situation, it should be related to the position detection system of the spindle, but carefully check all parts of the machine spindle, but found no defects.
Careful observation of the vibration pattern corresponds to the screw pitch of the X-axis, so the X-axis is checked again during maintenance.
Check the mechanical transmission of the machine tool, the structure is that the servo motor and the ball screw are connected by a synchronous toothed belt, and the position feedback encoder adopts a separate arrangement.
Check that the X-axis separate encoder is not in the same position as the lead screw, and there is eccentricity, that is, the encoder axis is not on the same line as the screw center, which causes the encoder to rotate during the X-axis movement. Uniform, reflected in the process, is the occurrence of periodic ripples.
After reinstalling and adjusting the encoder, the machine returns to normal.

Example 317. Failure repair without threading

Fault phenomenon: A CNC lathe with FANUC 0-TD system found that the machine does not execute the thread machining program during automatic machining.
Analysis and processing: CNC lathe machining thread, which is essentially the interpolation between the rotation angle of the spindle and the Z-axis feed. The angular displacement of the spindle is measured by the spindle encoder.
On this machine, because the spindle can rotate and shift normally, there are several reasons for analyzing the fault:
1) Poor connection between the spindle encoder and the spindle drive.
2) The spindle encoder is faulty.
3) The position feedback signal cable between the spindle drive and the CNC is poorly connected.
After checking that the connection between the spindle encoder and the spindle drive is normal, the first item can be excluded; and the display of the CRT can display the spindle speed normally, so the A, *A, B, and *B signals of the spindle encoder are normal; Using the oscilloscope to check the Z and *Z signals, you can confirm that the encoder zero pulse output signal is correct.
According to the inspection, it can be determined that the spindle position detecting system is working properly. According to the manual of the numerical control system, the thread processing function and signal requirements are further analyzed. It can be known that when the thread is machined, the system performs the spindle per revolution feed action, so it is related to the spindle speed arrival signal.
In the FANUC 0-TD system, the feed per revolution of the spindle is related to the setting of parameter PRM24.2. When this bit is set to "0", the "spindle speed arrival" signal is not detected during Z-axis feed; When set to "1", the "Spindle speed arrival" signal needs to be detected during Z-axis feed.
On this machine, the check finds that this bit is set to "1", so the feed can only be achieved if the "Spindle speed arrival" signal is "1".
Through the diagnostic function of the system, it is found that the "spindle speed arrival" signal is still "0" when the actual spindle speed display value coincides with the system command value.
Further inspection revealed that the signal connection line was broken; after reconnection, the thread processing operation returned to normal.

Example 318. Faulty repair that the spindle is slow and the "directional stop" cannot be completed.

Fault phenomenon: A data lathe using FANUC 10T system, during the machining process, the spindle can not perform the normal "directional stop" according to the command requirements, and the ERROR indicator on the control panel of the spindle drive "directional stop" is on. The spindle keeps rotating at a slow speed and the positioning cannot be completed.
Analysis and processing: Since the spindle works normally during normal rotation, the fault only occurs when the spindle is “oriented and quasi-stop”. It is therefore possible to preliminarily determine that the spindle drive is working normally. The cause of the fault is usually the same as the spindle “directional stop”. The sensor, the spindle position encoder and other components, as well as the mechanical transmission system installation and connection and other factors.
According to the maintenance manual of the machine tool and the system, the status of each signal in the PLC ladder diagram is checked against the fault diagnosis process. It is found that the spindle "directional stop" detection magnetic sensor signal is always "0" when the spindle 360o range is rotated. The cause of the malfunction may be related to this signal.
The magnetic sensor was inspected and tested with a screw driver as a "transmitted iron". It was found that the signal was operating normally, but the magnetic sensor signal was always "0" when the actual transmission stop was close.
After re-detecting the detection distance adjustment of the magnetic sensor, the machine tool returns to normal.

Example 319. "Directed quasi-stop" control board fuse blown fault repair

Fault phenomenon: A horizontal machining center equipped with FANUC 6M system often has a fuse S3.2A fuse on the spindle drive during normal machining.
分析与处理过程：该机床使用的是FANUC模拟式交流主轴驱动系统，且具有主轴“定向准停”(定位)选择功能，主轴驱动器上的熔断器S3.2A为主轴“定向准停”选择功能板的外部5V保护熔断器。
考虑到机床上主轴“定向准停”检测磁性传感器随机床主轴箱频繁上下运动，是最容易引起故障的部位，若连接不良较容易引起磁性传感器的5V短路，并引起集成电路损坏，导致S3.2熔断器的熔断。
维修时经过认真检查，逐一测量5V回路，最终发现主轴驱动器中的一片SN74148N集成电路已经损坏。
在对磁性传感进行重新连接，测量无短路后，更换SN74148N集成电路，故障排除。

例320．主轴定位速度偏差过大的故障维修

故障现象：一台配套FANUC llM系统的卧式加工中心，当执行M06换刀指令时，在主轴定向过程中，主轴驱动器发生AL-02报警。
分析与处理过程：主轴驱动器AL-02报警的含义是“速度偏差过大”。
为了判定故障原因，在MDI方式下，单独执行M19主轴定向准停指令，发现驱动器也存在同样故障。#p#分页标题#e#
据操作者介绍，此机床在不同的Y轴位置，故障发生的情况有所不同；通常在Y轴的最低点，故障不容易发生。
为了验证，维修时把主轴箱下降到了最低点，在MDI方式下，执行M19定向准停指令，发现确实主轴工作正常。
根据以上现象分析，可以初步判定故障可能的原因是驱动器与电动机之间的信号电缆连接不良的可能性较大。
维修时拆下电动机编码器的连接器检查，发现接头松动，内部有部分线连接不良。经重新焊接后，主轴恢复正常。

例321．主轴不能进行变速的故障维修

故障现象：一台配套FANUC 6系统的立式加工中心，主轴在低速时(低于120r/min)时，S指令无效，主轴固定以120r/min转速运转。
分析与处理过程：由于主轴在低速时固定以120r/min转速运转，可能的原因是主轴驱动器有120r/min的转速模拟量输入，或是主轴驱动器控制电路存在不良。
为了判定故障原因，检查CNC内部S代码信号状态，发现它与S指令值一一对应；但测量主轴驱动器的数摸转换输出(测量端CH2)，发现即使是在S为0时，D/A转换器虽然无数字输入信号，但其输出仍然有0.5V左右的电压。
由于本机床的最高转速为2250 r/min，对照表7-28可以看出，当D/A转换器输出0.5V左右时，电动机转速应在120r/min左右，因此可以判定故障原因是D/A转换器(型号：DAC80)损坏引起的。
更换同型号的集成电路后，机床恢复正常。

表7-28 指令、电压、转速对应表二进制转速指令S模拟输出/V 电动机转速/(r/min) 二进制转速指令S模拟输出/V 电动机转速/(r/min)
0000 0000 0000 0 0 0000 1011 0110 0.444 100
0000 0101 1011 0.222 50 1111 1111 1111 9.9999 2250