Page 2


500 Series

When replacing a Main CPU (QX-611-1) board on an M520 controller you must replace the EEPROM on the new board with the one from the old board. Then, you must clear the RAM. The procedure for this is:



This is the same procedure to initialize the memory.

1. Save all RAM data to an external device. (Programs,Tool,Parameters) 
2. Turn the NC off.
3. Set SW1 and SW3 on. (Move to the right)
4. Turn the NC on.
5. Wait for the green LED on the CPU to turn on.
6. Turn the power off.
7. Place SW1 and SW3 in their normal position. (Off)
8. Format the control.

The procedure for formatting is:

1. Load the Machine Parameters
2. Press the ALARM/DIAGN button.
3. Press the PLC-I/F soft key.
4. At the DEVICE prompt type 758. At the MODE prompt type S.
5. Press the INPUT/CALC button. (The prompts will disappear.)
6. Go to the I/O page and load the Parameters.#(3) INPUT/CALC.
7. Cycle control power.
8. Access the Machine Parameters #(1001) ( ) (M) TOOL/PARAM
9. The BASE Parameters will be displayed.
10. Scroll to page 6/8.
11. Set #6 fix_P to 1.
12. Go to the Data I/O screen.
13. Select ERASE.
14. Move the cursor to the right once and type FORMAT.
15. Press the INPUT/CALC button.
16. FORMAT COMPLETED should be displayed.
17. Go to the Data Input screen and enter #4.
18. Press the INPUT/CALC button.
19. This should load all of the fixed (canned) cycles.
20. Re-Load all Parameters, Tool Data, and Programs.
21. Go to the Machine Parameters (BASE).
22. Go to page 7/8.
23. Set #32 e2rom to zero.
24. Press the INPUT/CALC button.
25. Writing is done when "EEPROM WRITING" goes off.

The function of some of the switches on the DIP are:
SW1  MTOS Debugger
SW2  PLC Stop
SW3  Stop EEPROM transfer at power up.
SW4  Watchdog Alarm disable.

On an M520 Controller, QX611-1 is Main CPU. QX084 is Power Supply. QX531 is I/O. There are three LEDs on the QX522. The top one (green) is IOP SECTION CPU FUNCTIONING and should always be on. If it is off, you probably have either a bad QX522 or a bad cable. The middle one and the bottom one are FBAL1 and FBAL2. (Both red) These should always be off. If either one or both are on you probably have a problem with the Spindle Motor Encoder. (Not the orient encoder)This only applies if the Spindle Encoder signal is input through the QX522. In many cases, the feedback from both encoders is first input to the Spindle Amplifier and is transmitted serially along the data buss to the QX611-1. In this case the MTB may write design the software to prevent a control alarm but the LEDs will still be on unless the software tells the QX522 not
to look for a feedback input. Under these conditions the machine will function normally even with the LEDs on.

There are also three LEDs on the Power Supply. The top one (green) is Control Power On. The second one is AC FAIL (red). This one should always be off. If it is on the AC Input is either under or over or the 24vdc is being pulled too low. The third is BATTERY ALARM (red). This one should always be off. It comes on when the battery voltage drops below 2.6vdc.

The QX611-1 board has four LED's. Normally all of these will be Green with one or more flickering. If LED1 turns Red (Watch Dog Alarm) one of the PCBs may be defective. If LED2 turns Red (Memory Parity Error) the SRAM in the QX611-1 or one of the QX42_ cards may be defective.

If the control has a QX524 board, it also has four LED's. The first two should always be green meaning that data is being transferred between operation boards. If one or both are off there is probably a defective PCB or cable. The bottom two are FBAL1 and FBAL2 and have the same indication as on QX522.

There are two memory cassettes attached to the QX611-1 board. The one on the left contains the Executive Software. The one on the right (QX813) contains the Ladder.

Serial Buss:
The Serial chain starts at the CPU (QX611-1), goes to the left port on the X axis servo amp, leaves the right port, goes to the left port of the Y axis servo amp, leaves the right port, goes to the left port of the Z axis servo amp, leaves the right port, goes to the left port of the Spindle amp, leaves the right port, goes to the battery unit. The condition of the amps and the battery are monitored by the buss and the amps are controlled by the buss. The left port on the drives are always the Input and the right port is always the Output.

On an M500 series controller, if you set the software limits (OT+ and OT-) in Machine Parameters to the same value and sign (+/-) the stroke limits will be ignored. In this case, you can then set the software limits in the User Axis Parameters to the value you desire. There is also a User Axis Parameter (OT Check Off) which tells the control to ignore the values set in the User Axis Parameters. But no matter what the values are set for in User Parameters, they are superseded by any value in Machine Parameters.

There are two types of compensation on the M500 series controller. Type 1 and Type 2. Type 1 is used for machining errors at lower feed rates and Type 2 is used for higher feed rates.

In order to access the timers on an M520 controller:
1. Go to the Machine Parameters.
2. Press the TOOL/PARAM button.
3. Press the PLC soft key.
4. Page to [PLC TIMER].
5. Page to the timer you want.

On an M500 series controller the control type and serial number can be found on the main (startup) page.

To open the data window on an M500 series control, press the WINDOW button. This icon on this button is one rectangle (window) overlapping another. The window will open up to the last one used. If you want the window to display some other data press the button with two overlapping circles. When this is done three new soft key options will be displayed. They are:


If you press the W-SLCT soft key you will be given eight soft key options:


The NEXT key will show the next program block.

The METER button will show the Spindle load and RPM.

The WORK button will show the Work Coordinate page.

The HISTORY button will show the Operation History of the NC. This is especially useful in troubleshooting. It shows which output addresses have been activated. It lists them with the date and time of operation. They will be Y addresses typically in Hexadecimal. This can be very useful when trying to track down unexpected operation of the machine. Keep in mind that the window will not update while it is open. It must be closed then re-opened. So, if the window is open and you press a button such as the COOLANT button, no change will be seen in the window. If you close the window and re-open it by pressing the WINDOW button you will then see all of the Y addresses that were activated by the coolant function. This will only be the case if the machine are not displayed as Y addresses but rather by name. The buttons and the corresponding name assigned in the window are shown below.

MONITOR                 MON
CAN                         C.B.
INPUT                       INP
WINDOW                 WND
(                              (
)                               )
NEXT PAGE             NXT
LAST PAGE             BAK
TOOL PARAM          T/P
EDIT MDI                 E/M
DATA IN/OUT            I/O
GRAPHIC                GRA
DIAGN                     DIG
SFP                        SFP
FO                          F0
SHIFT                     No Change
; EOB                     ;
INSERT                   INS
+                            +
/                             /
=                            =
*                             *

All Alphanumeric buttons, ABC123, etc., are displayed as they are. A is A, B is B, 9 is 9, etc. The nine soft key buttons are shown as ME1 to ME9 for the buttons left to right. The BACK button is the button to the left of the first soft key (ME1). The NEXT button is the button to the right of the last soft key (ME9). The BACK button has a left pointing arrow, the NEXT has a right pointing arrow. These buttons are sometimes referred to as left and right chapter buttons. The Up Arrow button is shown as CRU (Cursor Up). The Down Arrow is shown as CRD (Cursor Down). Left Arrow and Right Arrow are CRL and CRR respectively. The diagonal arrow button is shown as ACT.

The window can be moved to any place on the screen. To move the window it must be highlighted in pink. To highlight the window, press the W-MOVE soft key. Once highlighted, use the arrow keys to move the window up, down, left or right. To scroll through pages of history, press the Diagonal Arrow button then use the Last page and Next page buttons to scroll.

The Date and Time displayed on the Operation History page is the same as the NC main date and time. If it is wrong, the main needs to be set. To do this:

1. MONITOR button.
2. C-MODAL soft key.
3. NEXT PAGE button.
4. #(1) DATA( )   ( )   ( )
    This sets the date Year, Month, Day in the parentheses from left to right.
5. #(2) DATA( )   ( )   ( )
    This sets the time Hour, Minute, Second left to right.
6. INPUT button.

The clock does not differentiate between AM and PM, so it is a good idea to set it up for Military time. This is done simply by entering the hour as Military ( 13:00 for 1 PM, 14:00 for 2 PM, etc.)

Also in the C-Modal screen you will find the Parts Counter, NC Power On Time and Time of Automatic Operation. These can be changed and reset here using the same basic method for changing time and date.

On the M500 series control it is possible to do buffer correction. That is, if a programming error occurs, it is not necessary to reset the control to correct the program. You can correct the problem and continue on with the program. For example, if you experience alarm P62 F-CMD NOTHING. This usually means that a line of code containing a feed command does not have a feed rate command with it. When the alarms occurs, press the PROGRAM soft key on Page 2 of the POSITION screen. Now, press any of the cursor or tab keys. (Tab keys are those arrow keys arranged in a sort of big plus sign in the lower left of the CRT/MDI normally used to move through data fields). Doing this will establish the Buffer Correction mode. The display area for the program being executed changes to the buffer correction area. BUFFER EDIT is displayed. Cursor to the problem area, in this case the line where the feed command is located and correct the problem. The only corrections you can make is for those items in the display area. So, in other words, you can't use Buffer Correction mode to change things all throughout the program. After making the correction, press INPUT. The display area returns to the program being executed and the alarm message is cleared. Press Cycle Start, the program resumes where the alarm occurred.

When adjusting backlash on a Mitsubishi M500 series controlled machine:

Machine Axis Parameter 11 G0back sets compensation amount during JOG and RAPID.

Machine Axis Parameter 12 G1back sets compensation amount in HANDLE mode and during commanded movement (cutting feed).

If a machine leaves bumps at the quadrants during circular interpolation, there is more than likely a lost motion (backlash) problem. As with all controls, the adjustment is done by Parameter and is broken down by the axis. In the case of an M500 series control the parameter is #16 of the Machine Servo Parameters.

#                 X    Y   Z
16  SV016   0    0    0

The setting range is 0 to 200%. Most machines have this parameter set at 0 and seldom is it required to be more than 100%. There is no direct mathematical correlation between the setting and the actual amount of backlash. In most cases, the best procedure is to try different settings until a circle can be machined in a test piece without leaving a bump. Afterwards make sure the circle is still round and within size tolerance. Most of the time when there is a bump it is due to overcompensation so the value in the parameter needs to be decreased.

Another parameter to be aware of is #41(SV041). This parameter allows you to compensate one amount in the positive direction and another amount in the negative direction. If SV041 is set to zero, as it is in most cases, the compensation is performed according to the value of Parameter SV106.

One very, very important thing to know about the Ladder of an M500 series control is that most of the time when you open it up, depending on the machine builder, comments will not be displayed. In order to display them, press the EOB button. At the bottom of the display a message will be shown that says DISPLAYING COMMENTS. When you display the comments, some of the instructions will change. For example the instruction M162 might become CL1.

Another thing to know is that if you are trying to use the ladder to troubleshoot a problem, you can view several rungs on the same screen even though they might be many steps apart. For example, if you are trying to find out why the coolant won't come on you can search and display the rung with the coolant button. This may be step 500. If an instruction related to this one is at step 350 and you search it, it will be displayed on the same screen with step 500 so you can view them both at the same time.

The connectors of an M530 I/O board from top to bottom are:


CDP11 and CDP12 are for Inputs. CDJ11 is for Outputs.

In the unlikely event you should need to replace the CPU (QX141-1), keep this in mind. If you replace it with a new one, you need to backup Parameters, Tool Data and Programs. You must also write down Latch Parameters and Bit Selects. Tool Offsets will load in with the Tool Data but the Tool Register will not, it stays with the old CPU. PLC timers will load back in with the Parameters as well as Position Switch information. The Latch Parameters will stay with the old CPU.

If a program will not execute and there are no obvious reasons such as alarms etc., check the In-Position signal of each axis. This may also keep the spindle from running in Manual mode. In the case of an M500 series control, the In-Position Width is set in Machine Servo Parameter SV024. The setting range of this parameter is 0-32767. The value is um.

On an M520 Control, User Axis Parameter #13 OT-CHECK OFF set to 1 tells the NC to ignore the values in #14 and #15 (Soft Travel Limits). The Parameter is Axis specific so be sure to look for the Axis name at the top of the screen.

If you have trouble communicating with an M530 control, check for abnormal voltages at the connectors particularly the QX524 board. A grounded wire on the external 24 volts can cause communications problems.

To set tools on an M530 control, go to the TLM (Tool Length Measure) page. Zero Return the machine. Cursor to the H number you want to store the height in. It can be any number. Bring the tool down with the MPG. When you are touching the part, press INPUT. Enter the cutter radius into one of the D numbers. It can be any number. In your program when you call the tool, call the offsets. I.E. T1 M6 H4 D9;

If an M520 or M530 control displays EMG EMERGENCY LIN, check the 220 volts that feeds the drives.

Normal voltage reading on the RS-232 port for the M520 and M530 controls are:

Pin 2 to GND  -  11.5 vdc
Pin 3 to GND  -      0 vdc
Pin 7 to GND  -      0 vdc
Pin 2 to Pin 7  -    12 vdc
Pin 3 to Pin 7  -      0 vdc

To find the software version on an M530 control, press the DIAGN button then the NC-SPEC soft key. Look in the lower left hand corner.

To find the PLC version on an M520 control, look in the left hand corner of the ALARM SCREEN. On an M530 control, look in the left hand corner of the MONITOR SCREEN.

The Ladder for an M520 control is stored on an SRAM card which is located in the right hand CBUS slot on the CPU board. The Mitsubishi designation is QX812. In the case of an M530 control it may be a QX815.

If you need to change the reference return position of an axis of an M530 control you must make an adjustment to the Reference Point Shift Amount. This parameter is found in the Machine Parameters under Zero (Reference) Point Return Parameters. The setting range is 0-65535u. The value you see in this parameter is microns. To find the shift amount in millimeters, multiply by the value in the parameter by .001. So, if you needed to shift the ZRN position of an axis by .120", for example, convert to microns. The conversion factor from inches to microns can be hard to handle, it may be best to convert to millimeters then to microns. That, or trial and error. The procedure is:

 1. Press DIAGN IN/OUT button.
 2. Press PLC-I/F soft key.
 3. # (1001) DATA( ) MODE( M )
 4. Press INPUT CALC button.
 5. Press TOOL PARAM button.
 6. Press ZP-RTN soft key.
 7. Press Right Chapter key until desired axis is displayed at the top 
     of CRT.
 8. Change #3 G28sft to desired value.
 9. Press INPUT CALC button.
10. Cycle power.
11. Perform Reference return.
12. Check position.

There is a condition that can occur on M520 and M530 controls which can be very difficult to troubleshoot. In this case the machine will be in an E-stop condition even though the E-Stop circuit on the machine side is clear. Input address X27 which is used by most machine builders for the E-Stop circuit will be 1 as it should be if the E-Stop circuit is closed. The CRT will display EMG at the bottom left and the READY lamp on the monitor will be off. This condition can be the result of a power surge which damages the CPU board. Also the diagnostic bits normally used for troubleshooting, R69 will all be ones and none of the drives will indicate an alarm state.

On most machines controlled by an M520 or M530 control, the MCC contactor is energized by a normally open relay contacted in the CV unit if the NC is in a READY state. There are three terminals near the bottom of the CV unit that are labeled L11, L21 and MC1. Typically one phase of the AC line (220 vac) will be connected to the L11 terminal and another phase will be connected to the L21 terminal. When the NC boots up and wants to make the machine READY, it will close a relay within the CV unit which feeds the power from the L21 terminal onto the MC1 terminal which is connected to one side of the MCC coil. The other side of the coil is connected to either the source for the L11 terminal or to the third phase of the incoming AC (L31, L3, T, etc.) At this point MCC should energize sending all three phases of the AC to the main terminals of the CV unit which charges the DC link in turn powering the servo drives and the spindle drive. If the CV unit closes this contact and for some reason MCC does not energize (open coil, loose wire, etc.) the following indications will normally be observed:

EMG EMERGENCY PLC displayed at the top of the screen.
S01 SERVO ALARM : PR 0071 S1 displayed below it.
EMG displayed at the bottom of the screen.
The CV unit will display H.
The spindle amp will display F3 and 71 flashing and alternating.
The servo amplifier (if dual amp on two axis machine) will display F2 and E7 flashing and alternating.

In order to view the ladder on an M520 control, Bit Select parameter needs to be 1. If this parameter is 0 on an Ecoca EL machine, when the FO button is pressed the TEACH-IN screen will be shown regardless of the setting of the PLC-SW for TEACH-IN.

If the cable is removed from the battery pack (MDS-A-BT2) on an M520 controlled two axis machine (EL, etc.), the CRT will display the following:


The M520 controller has 103 timers. They are accessed through the Machine Parameters. T0 to T15 have a base value of 10 milliseconds. T16 to T103 have a value of 100 milliseconds. So, if you go to T1, for example, and the number displayed is 50, the timer setting is 50 times 10 milliseconds or .5 seconds. If T17 displayed 50 then the timer setting would be 5 seconds.

To page through the ladder of an M520 controller rather than searching addresses over and over:

1. Press the FO button.
2. Press the LADDER soft key.
3. Press the 2CIRCUIT soft key.
4. Press the MENU soft key.
5. Press the 6MONIT soft key.
6. Press the SHIFT button.
7. Press the + button.
8. Press the INPUT button.
Now, every time you press the INPUT button the monitor will display the next several rungs of ladder. On some machines you may need to press the + button without pressing the SHIFT button. In some cases it may not work if you have already been searching by address so you will have to press the F0 button to go back to the LADDER soft key and start again.

BIT SELECTION Parameters for PLC development on the 50 control per manual BNP-B2063A:

#6451.0    0 = On-board Operation OFF. On-board operation is off. Nothing will display even if FO is pressed.
               1 = On-board Operation ON. Screen is displayed for user PLC development, ladder monitor and ROM writing, etc.

* Note - Mitsubishi refers to manipulation of the ladder at the CRT as​ On-board programming.

#6449.0    0 = Timer Setup Value SCREEN on.
               1 = Timer Setup Value PROGRAM on.

#6449.1    0 = Counter Setup Value SCREEN on.
               1 = Counter Setup Value PROGRAM on.

When 6449.0 and 6449.1 are 0, the values set in the PLC TIMER and PLC COUNTER screens SETUP PARAMETERS are used as the timer and counter setup values.

When 6449.0 and 6449.1 are 1, the programmed constant (K) values are used as the timer and counter setup values. At the time, the programmed constant (K) values of the timers and counters are also displayed on the PLC TIMER and PLC COUNTER screens of machine manufacturer parameters. So, even if both bits are set to 1, the valid setup values can be checked on the screens in the PLC-RUN state. But no values can be set. If a value is set, the alarm E05 Setting Disabled is displayed. When 6449.0 and 6449.1 are both set to 0, the constant (K) values are ignored and the values set on the screen become valid but since K cannot be omitted in programming, any numeric value must be entered in K for programming.

#6449.2    0 = Integrating Timer (T96-T103) Retention OFF (No retention)
                1 = Integrating Timer (T96-T103) Retention ON

#6449.3    0 = Counter (C0-C23) Retention OFF (No retention)
                1 = Counter (C0-C23) Retention ON

When 6449.2 and 6449.3 are 0 the current values of the integrating timer and the counter are reset to 0 when the NC power is turned off.

When 6449.2 and 6449.3 are 1 the current values of the integrating timer and the counter are not reset to 0 even if the NC power is turned off. The values before the NC was turned off are retained.

#6452.2 0 = Integrating Timer (Q136-Q151) Retention OFF (No retention)
            1 = Integrating Timer (Q136-Q151) Retention ON

#6452.3 0 = Counter (B0-B103) Retention OFF (No retention)
            1 = Counter (B0-B103) Retention ON

When 6452.2 and 6452.3 are 0 the current values of the Integrating and the counter are reset to 0 when the NC power is turned off.

When 6452.2 and 6452.3 are 1 the current values of the integrating timer and the counter are not reset to 0 even if the NC power is turned off. The values before the NC was turned off are retained.

On a Mitsubishi M520 controller the direction in which the trace is drawn for the graphic function is set in the [TRACE SETUP] screen. The screen looks like:


#1 $ NO.1 (1)
  2 AXIS DIRECTION (0) (1) (+=0, -=1)

  3 $ NO.2 (0)
  4 AXIS DIRECTION (0) (1) (+=0, -=1)


The direction of the trace, left to right, is determined by the placement of the 0 and the 1 for the AXIS DIRECTION field. Using #2 as an example:

  2 AXIS DIRECTION (0) (1)
  This will cause the trace to be drawn from + to -.

  2 AXIS DIRECTION (1) (0)
  This will cause the trace to be drawn from - to +.

An important point to remember about the graphic function is that the direction parameters shown above cannot be changed if the Trace function is active. Attempting to do so will cause E05 NOT ACCEPTABLE alarm to be issued. To determine if the Trace function is active, go the graphic display screen (where the trace is actually shown). Look for the TRACE soft key. If it is highlighted, the Trace function is active. Press the TRACE soft key to deactivate the function.

If the absolute position for an axis is lost (Z70) you may need to initialize the absolute pulse coder. In most cases, however, you may solve the problem by loading the machine's parameters.

If you do initialize the pulse coders remember that if you need to change the value that is set in the BASE (#2) parameter you have to have 1 set in the #1 SET parameter to keep from getting the alarm E05 NOT ACCEPTABLE. In other words you should change the value of #2 BASE immediately after setting the zero point.

The procedure for initializing the Absolute Position Coders:

1. Access the Machine Parameters.
2. Press the TOOL/PARAM button.
3. Press the Scroll button until page 5/10 of the BASE parameters 
   (Absolute Position) is displayed.
4. Enter 0 into the # ( ) field.
5. Press Input. ABSOLUTE will become highlighted.
6. Enter 5 into # ( ) field. 5 corresponds to NO STOPPER.
7. Cursor to the DATA field ( ) which corresponds to the axis you wish 
    to initialize.
8. Enter 0 and press INPUT.
9. With the machine in manual mode, move the axis to the desired zero 
10. Enter 1 into the #( ) field. This corresponds to SET.
11. Enter 1 into the DATA field ( ) of the axis.
12. Press INPUT.
13. The ABSOLUTE display of the affected axis will change a few times 
      and if the initialization was successful will end up displaying *.
14. Enter 5 in the # ( ) field.
15. Enter 1 in the DATA field of the axis and press INPUT.
16. Repeat these steps for all axes desired.
17. Cycle power.

On step 10 you must put a value into the field of both axes, not just the one being set. This value can be 0. If a value is not set, The SET parameter will become 1 but step 13 will not occur. The absolute display will show 1 and will stay 1 until power is cycled.

# (2) BASE cannot be changed unless #(1) SET = 1. This will cause E05 NOT ACCEPTABLE to be displayed.


Mitsubishi M50 controllers look very much like the M500 series but differ in many ways.

On an M50 controller, if you want to view the macro programs change Parameter 1121 to 0.

On a Mitsubishi 50 controller the PLC is stored in non-volatile ROM. The ladder can be loaded via RS-232.

If the 50 controller displays NO MODE check the NC-SPEC page, if no data is displayed beside PLC the PLC is gone. 
In order to access the Machine Parameters in an M50 control you cannot use 1001 M. You must:

1. Press the TOOL/PARAM button.
2. Press the SETUP soft key.
   You will see the prompt "Open the menu setup parameters?"
3. Enter Y
4. Press the INPUT/CALC button.

A key point to know about an M50 controller as well as, in some cases, the M500 series controller is that you may be required to press the INPUT/CALC button more than once. An example is when trying to open the Option Parameters in a 50 controller.

Just like an M500 series controller, it may sometimes be necessary to initialize a 50 series controller. The procedure for doing this is:

1. Turn the NC power off.
2. Open the cover over the LED display of the Control Unit.
3. Turn the rotary switch CS2 from it's normal position of 0 to position 6.
4. Turn the NC power on.
5. The LED display on the Control Unit will count up to 60 then stop.   This will take about 20 seconds, the CRT will be blank except for 
    the cursor.
6. Turn the NC power off.
7. Rotate CS2 back to 0.
8. Turn the NC power on.
9. The CRT will display: SELECT NC TYPE
    #( )
    Enter the type i.e. 2 for a mill.
10. Press the INPUT/CALC button.
11. The CRT will display: SELECT AVR TYPE
     AC 200V:1
     AC 100V:2
     DC 24V :3
     Enter the number corresponding to the incoming supply voltage. In most cases this will be 220, 230, etc.
12. Press the INPUT/CALC button.
13. Cycle the NC power.

Don't be surprised if the machine comes back up in Chinese. This can be easily fixed by changing parameter 1043 lang.easily fixed by changing Parameter 1043 lang to 1. The problem is that the soft keys are in Chinese so you have to go on memory or do this:

1. Press the TOOL/PARAM button.
2. Press the second soft key from the right (MENU). In this case, the 
    Right Chapter button is counted as a soft key so it is the second 
    button from the right.
3. Press the third soft key from the right (SETUP).
4. Enter Y.
5. Press the INPUT/CALC button.
6. Page over to Machine Base Parameter 1043 lang.
7. Enter 1 in the DATA field.
8. Press the INPUT/CALC.

The next time you change screens, it should come up in English.

Another thing that may happen is the controller may come up with no memory, that is: CHARACTERS 0 PROGRAMS 0.
This will cause the message E51 FILE OPEN ERROR to be issued when certain functions are attempted.

To correct this you have to format the controller. Just as with other procedures this does not work the same as formatting an M500 series control. To format the 50 controller:

1. Change Machine Base Parameter 1060 SETUP to 1.
    The controller will ask if you want to initialize. The answer is NO.
2. Enter N.
3. Press the INPUT/CALC button.
4. Enter Y.
5. Press the INPUT/CALC button.

Yet another effect of initializing is that the machine may come back up in Metric instead of Inch. If the machine builder has not provided a PLC-SW as is the case of Initial Inch on Takumis you can put the machine in inch mode with Machine Base Parameter 1041 I_inch. After initializing this parameter may have a number or a letter value. Changing it to 1 should make it inch. Cycle NC power.

The Ladder and Graphic functions may also now be absent. These are often specified by the machine builder by Bit Select, etc. Also be aware that initializing will cause the loss of option parameters that must be put back.

If when trying to perform Input/Output functions, you get the message DATA PROTECTING, the edit lock is turned on for that function. You can check the status of these locks by going to the Input/Output screen. You will see something like:

#1   MAIN PROGRAM          ABC
#2   TOOL DATA                  ON
#3   PARAMETER                ON
#5   COMMON VARI.            ON

Wherever the word ON appears, that area is locked for editing and must be changed to OFF in order to perform Input/Output operations in that area. In the case of MAIN PROGRAMS, A,B and C are different types of edit locking, to edit the main programs with respect to the type of editing that letter (A,B or C) must be removed from the screen. All of these are normally addressed by the machine tool builder with either edit keys, Bit Selects, PLC switches, Latch Parameters, etc. If these are not available or unknown there is another way. There are four Y addresses which in different combinations will turn these locks off. They are Y238, Y239, Y23A and Y23B. Changing Y238 to 1 will turn the TOOL DATA lock off. Making Y239 1 will turn the PARAMETER and COMMON VARIABLE lock off. However, changing one of the four addresses may change another one back to 0. After a little trial and error you can find the right combination to get the things unlocked that you want or you can just make all four Y addresses = 1. This will turn all of the locks off. When changing the addresses it is the same as on an M500 series, you are forcing the Y address to go high. For example,

# (Y238) DATA(1) MODE(2)

If you cycle power, the force will turn off so the control will come back on with the locks on. You will have to force them again.

On the M50 series controller as with the M500 series the PLC can be made to stop or run by accessing the ladder functions.

1. Press the FO button.
2. Press the MENU soft key.
3. Press the FILE soft key.
4. Press the RUN/SP soft key.
5. Enter 1.
6. Press the INPUT button.

To place the PLC in run again, repeat the procedure but enter 0 instead of 1.

Another way to stop the PLC is to open the LED cover on the Control Unit. Place the machine in E-Stop mode. Rotate CS2 to position 2.

The Machine Parameters in a 50 series controller are actually called Setup Parameters by Mitsubishi but in this file I call the Machine Parameters most of the time.

To erase all of the programs registered in memory of a 50 series controller:

1. Press the DATA IN/OUT button.
2. Press the ERASE soft key.
3. Enter CLR in DATA field 
    #( ) DATA(CLR)
4. Press the INPUT CALC button.

Unlike an M500 series controller, the PLC of an M50 series controller is not stored on a Memory Cartridge. It is stored in ROM in the Control Unit. If the Control Unit is badly damaged the PLC may be lost.

On Mitsubishi controllers, the PLC can be written at the controller. There are manuals to help with this. In the case of a 50 series controller, the manual is BNP-B2063A (ENG) PLC ON-BOARD INSTRUCTION MANUAL.

Switches and their settings of a 50 controller:
SW1 (Slide Switch) for normal operation is in down position.

CS1 (Rotary Switch) Channel Selection for CRT changeover. For normal operation set to position 0.

CS2 (Rotary Switch) System Selection switch.
Position 0      Normal operation.
Position 1      PLC program Stop.
Position 2      Normal operation after reading parameters from EEROM Setup after losing parameters.
Position 3      For operation using MELSEC peripheral equipment instead of communication terminal.
Position 4      Not used.
Position 5      Not used.
Position 6      Initialization of memory and default setting of parameters. Memory is set to default settings and EEROM is rewritten.
Position 7-F   Builder Maintenance mode.

To access the PLC-SW on a 50 controller, press the MONITOR button then press the MENU button until the PLC-SW soft key is displayed.


The Mitsubishi 64 controller is much like the 50 series. The parameters are numbered the same way. To get into the "machine parameters" you have to select yes when prompted to "OPEN THE MENU SETUP PARAMETER".

To access the communication parameters on a Meldas 64 controller:

1. Press the TOOL PARAM button.
2. Press the I/O PAR soft key.


The 300 series controller has an adjustment for the brightness of the CRT. It is on one of the boards of the CRT unit, it is labeled RV402. It is mounted horizontally and the outer cage must be removed to make the adjustment.

The Mitsubishi FX-10 and FX-20 wire EDM machines use an M320 controller. After turning the power on, you must press the READY button to bring the controller up. It is not uncommon for one of these machines after being without power for a couple of weeks to need its software reloaded. When this happens the screen will be blank. If you place the SYSTEM LOAD/SYSTEM START switch (this is the toggle switch below the floppy drive) from the SYSTEM START position to the SYSTEM LOAD position and power back up, you should have a screen. Reloading the software will erase all programs, offsets, E-Packs, soft limits, timers, etc. The procedure for loading the software is:

1. Place SYSTEM LOAD/SYSTEM START switch (at floppy drive) to SYSTEM LOAD.
2. Insert SYSTEM SOFTWARE disk 1 of 3 in the floppy drive.
3. Press INPUT.
4. When prompted "ARE YOU READY?", insert disk 2 of 3. Once all three 
    disks have been loaded...
5. Cycle power.
6. Move switch to SYSTEM START.
7. Insert the ENGLISH DISK (Make sure the software version is the same 
    as the other disks).
8. Cycle power. (Display will say "LOADING LANGUAGE")
9. Once a normal screen is displayed (position, offset, etc.) remove 
    the disk. Lower right corner will display "LOAD PITCH ERROR"
12. Press 5 (corresponds to soft key option [I/O])
13. At DEV ( ) enter 1 (for MFD (floppy disk) ) DEV should be 
      highlighted before entering the one.
14. Press INPUT.
15. Press the right arrow key until "I/O MODE" is highlighted.
17. At I/O MODE ( ), enter 1 for IN (Input).
18. Press INPUT.
19. Press the down arrow key until "PROGRAM NO." is highlighted.
20. At PROGRAM NO. L ( ), enter "ALL".
21. Press INPUT.
22. Press 1 (I/O START).

You will be prompted that data is being loaded and when it is complete.

Once the software has been loaded you have to load the E-PACKS. These are the 9000 series programs which perform various functions.

To load the E-Packs:

1. Insert the E-Pack disk. (Normally, an E-Pack disk will have three or four files on it but generally speaking you only need to load the first file on the disk).
2. Press the PROGRAM EDIT key.
3. Press soft key number 5.
4. Press 1 (INPUT MODE).
5. Press INPUT.
6. Cursor to DATA KIND.
7. Press 1 (NC PRO.)
8. Press INPUT.
9. Cursor to MFD FILE.
10. Type in the file name.
11. Press INPUT.
12. Press soft key number 1 (I/O START).

You will be prompted that data input is complete.

On the 320 controller, connector CNP3 on the chassis power supply is a three pin Molex connector which supplies 110 vac to the CRT. On the Mitsubishi FX-10 and FX-20 EDM machines the wires from this connector go to the CRT ON/OFF switch. On this power supply the incoming power (100vac) is supplied to terminals ACINH and ACINL.

The magazine capacity for the Max-3 Rebel with the 335 controller is stored at R1905 in the form of a decimal number.

If the tools get confused on the Max-3 with the 335, manually move the magazine to pot number one. Make R1901 = 1 and make R1905 = the magazine capacity.


On a 635 controller, when prompted to enter a password to access the Machine Parameters, enter MPARA. 

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The information on this and subsequent pages is intended to supplement and reinforce the knowledge of competent machinists and technicians. The authors of this website are in no way liable for damage or injury resulting from the improper use of the instructions contained herein.