A short scenario of a Melservo Motor replacement and the migration requirements thereof.


The scenario

HF-SP152 Servo Motor requires replacement

The Current Control System in place:

  • Servo Motor – HF-SP152
  • Servo Amplifier – MR-J3-200B 
  • Motion Controller – Q173DCPU 
  • CN1A & CN1B are Interconnected              


The Problem;

Melservo MR-J2s and Melservo MR-J3 systems are disconitinued. This refers, especially to the Amplifiers and Motors.

Therefore, a Migration Replacement strategy is required. That being said – it must be understood that – when it comes to the recycling pf older components for the upgrade – then, at best;

  1. Old motors can work with newer amplifiers
  2. Old amplifiers cannot work with newer amplifier

This is because the encoders of the new motors cannot be managed by the old amplifiers. 

(note – this is a best-case scenario. In many cases – both the motor and amplifier are to be replaced.


The Solution

Since the motor requires to be replaced, and it is discontinued – both the motors and the amplifier are to be replaced.

Ideally, a servo system to be selected – needs to be compatible with the PLC CPU and Motion controller in the system.

The migration path for MR-J3-B is MR-J4-B. 

The following strategy applies;

The Amplifier migration is given as follows;

As for the motor – the migration path is as follows;

The Melservo Selection tool

From here – a hardware solution will be identified. This solution will include all of the main Melservo components (amplifier and motor) as well as the auxilliries equipment (cables, connectors and batteries).

The Melservo selection tool can be accessed as follows:

The following results are applicable:

The conclusion. 

First – the communication protocols;

  • The Melservo MR-J3-B amplifier works with SSCNET III communication protocol.
  • The Melservo MR-J4-B amplifier works with SSCNET III/H communication protocol.

This means that the MR-J4-B amplifier can indeed work with the existing Motion Controller – Q173DCPU – but the amplifier is to be put in SSCNET III mode.

Also – For smaller MR-J3 amplifiers and motors, the MR-J4 amplifiers and motors are compatible with the cables. 
This includes compatibility for: encoder cables, power cables, sscnet communication cables and  I/O connectors.

(Once again – this is not the case for larger Melservo systems). 

In conclusion – the final hardware replacement requirements would be:

  • HG-SR152 (Melservo Motor)
  • MR-J4-200B-RJ (Melservo Amplifier)
  • MR-BAT6V1SET (Melservo Battery)

And addition – if programming cables and software is required; 

  • MR-J3USBCBL3M (USB Programming Cable)
  • MR-Configurator2 (Engineering Software)

Note that both the MR-J3 and MR-J4 Servo amplifiers use a mini-USB programming cable. Also, MR Configurator (legacy hardware) is included on the MR Configurator 2 (new hardware) – Engineering software. Therefore, all Melservo Amplifier products can be accommodated.