Mitsubishi CNC | M70-M80 Series | Drive System and Axis Removal


This article is intended to disable one or more axes on a multi-axis machine with M70/M700/M80/M800 series.

The main purpose is to teach how axes are activated in the CNC, and related parameters. Once you understand the basics, adding or disabling an axis can be done in the same way.

This is not recommended to do by the end user.


#1021 mcp_no
#3031 smcp_no
#1070 axoff
#8201 Ax. release
#2018 no_srv
#2049 type

Parameter descriptions and their use will be explained in following of article.

Drive System Structure

Figure 1. Sample Drive System Structure for Mitsubishi CNC controlled milling machines ( 4 axis + 1 Spindle )

The above figure actually refers to 2 identical systems.

The reason for being shown separately is because physical arrangement of the drivers could differ. We can sort our drives in the order we want. The important thing is the numbers on the rotary switches on the drives. The drives are connected optically. This connection can be seen as a serial connection. All the drives are in one line, a so called bus line. The rotary switches of each driver are used and the parameters are adjusted accordingly.

When showed that it is the first step of the bus (A), it represents the optical servo cable coming out from the NC and starts by connecting the bus line to the CN1A socket. It continues in a sequential manner from teh same drive as the CN1B port to next drive.
End of the bus indicated as (B) may have been closed with a terminator connector.

Rotary Switches and Related Parameters

Each drive has a rotary switch from 0 to F. This switch is used to identify the axis within the drive-system. For example, rotary switch=0 , identified as axis 1.

In order for the system to identify this, the related parameters are # 1021 and # 3031.

#1021 mcp_no : Axis sequence number
#3031 smcp_no : Spindle sequence number

Example configuration for machines with 4 axes, 1 spindle;

#1021 mcp_no : 1001, 1002, 1003, 1004
#3031 smcp_no : 1005.
1001: System $1, first axis. Rotary switch on servo: 0.
1002: System $1, second axis. Rotary switch on servo: 1.
1003: System $1, third axis. Rotary switch on servo: 2.
1004: System $1, fourth axis. Rotary switch on servo: 3.
1005: System $1, fifth axis (spindle). Rotary switch on servo: 4.
#1021 mcp_no: Values written in the parameter are expressed as X in axis 1, Y in axis 2, Z in axis 3 and A in axis 4 (machining center).
#3031 smcp_no: Values written in this parameter refer to the spindle drive.

Axis Detach

In M70/M700/M80/M800 series, there are 2 ways to disable the drives. Hardware disable and software disable.

Software Detaches

Parameters for Software Detach

#1070 axoff
#8201 Ax. Release
#8201 Ax. Release: 1 activates the axis detach function. Other prm settings also needed.
#1070 axoff: 1 and also #8201 set to 1, = axis disabled.
In this setup the motor and drive cannot be dismantled.

Hardware Detaches

Parameters for Hardware Detach

#2018 no_srv,
#2049 type

First #2018 no_srv is set to 1 and the machine is turned off.

Depending on the type of servo-drives, following changes need to be made before drive detach.

  • If the drive is MDS – A/B/C1/CH series, set ROTARY SWITCH on corresponding drive to F ( These series drives are not using with M7 and M8 series controller. If you see that series model drives, check the controller type again. )
  • If the drives is MDS – D/DH/DJ or E/EH/EJ/EJH series, ROTARY Switches are not to be touched. Under the Rotary switch you find DIP Switches. The leftmost DIP switch is put in upper position = axis not used. If it´s a 2-axis drive, DIP next to the leftmost is also changed to upper position.

Below a short description of the drives.

This axis is disabled when #2018=1. By changing the switches on the drive, we are physically disabled.

If desired, the drive can be deactivated by removing the drive directly from the bus line without touching the switches.

The drive can be disconnected and the cables transferred to next drive without disrupting the serial connection shown in Figure 1.

If desired, the driver and/or motor can be disassembled.

If the absolute system alarm or the Emergency stop occurs, set the parameter #2049=0. We do not have to change #2049 if there is no alarm.

When the drive is reinstalled, set #2049 to original value, reference point setting for the axis need to be done.

In some cases, if the alarm is still present when the drive and motor are dismantled, the manufacturer may have some signals in the PLC ladder related to the axes.

In addition, sometimes there is a PLC switch that disables axes controlled by ladder (PLC Switch menu).

This switch needs to be used. In such cases please consult the manufacturer.

This is not recommended to do by the end user. Please have a call service center for authorized engineer.