Setting robot additional mechanism (external)

Setting robot additional mechanism (external)

The article describes how to set and program robot additional servo axis as a separate mechanism (for example rotary table). The detailed information can be found in:

The article do not describe how to wire a servo drive. Please use a separate user manual for servo drives.


Basic equipment
  1. Servo set: Mitsubishi Electric MR-J3-B or MR-J4-B series (amplifier+motor)
  2. Serwo battery: MR-J3BAT (connect to servo amplifier)
  3. Fiber cable: MR-J3BUS3M


  1. RT Toolbox3
  2. MR Configurator2


Connect the fiber cable to AXIS connector in controller and CN1A in serwo amplifier. Follow the pictures below.

Servo settings

Address setting

Servo settings in MR Configurator2

Connect directly to serwo amplifier by USB mini cable. Run MR Configurator2 and set a parameter in picture below.

I f you don’t have emergency button connected then deactivate Forced Stop function. Otherwise the emergency error will occur.

Anyway it is recommended to connect emergency wiring from the beginning of work (details in ROBOT ADDITIONAL AXIS FUNCTION MANUAL or SERWO MANUAL).
If a robot is stopped by Emergency Stop function, the additional robot axes will be also stopped. The signal is sent by fiber cable.

Write the parameters and perform servo restart.

Robot parameters 

1. Open Robot additional axis parameters in RT Toolbox3.

2. AXUNUM parameter set to “1” (one additional mechanism existance).

3. Select first line in a table (first additonal servo)

4. Click Set... button

Additional axis 1 parameter window will appear. Set basic settings.

Basic settings:

AXMENO – mechanism number (1 – robot, 2 – additional mechanism); set 2 for rotary table

AXJNO – axis number in a specified mechanism; set J1 axis for rotary table (first axis in mechanism no 2)

AXGRTN, AXGRTD – insert mechanical gear ratio of your rotary table

AXUNIT – choose unit system; set 0:deg for rotary table

MEJAR – insert low and hight movement limits. Watch out the limitation for movements limits min/max values (see the manual)

AXSPOL – set rotation direction

The other parameters can be left default.

Write the parameters and perform robot restart.

The additional axis now should be recognized. In servo display "b01" message should appear.

Origin settings

At first running the origin settings must be done for the additional axis.

Move the additional mechanism (rotary table) to the position where zero will be set and perform origin setting. Follow the picture below.

Now the additional mechnism is ready for usage.

JOG in additional mechanism

Use a robot Teaching Box. Switch to mechanism number 2 (2:USER). 

And like with robot: perform SERVO ON and use +/- buttons for mechanism control.



Additional mechanism is controlled from separate program (multitasking mode)

Each program must start with GetM command (GetM 1 for robot program, GetM 2 for mechanism program)

Data exchange between programs is performed by external (global) variables (use predefined M_00, M_01,…, P_00, P_01,… or user defined)

Programs example:

'pr1 main program (robot arm)

GetM 1   

M_01=0      'global variable 1

M_02=0      'global variable 2

If M_Svo(1)=0 Then Servo On            

If M_Run(2)=0 Then XRun 2,"pr2"       'run Program 2 for additional mechanism

Wait M_Run(2)=1

mov p1

mov p2

dly 0.5

m_01=1         'add mech movement permission

wait m_02=1        'wait for add mech movement end

mov p1



'pr2 second program (additional mechanism)

GetM 2

If M_Svo(2)=0 Then Servo On

wait m_01=1        'wait for movement permission


mov p1

mov p2

mov p1

m_02=1        'end movement confirmation


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