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MELSERVO-J4 Series Servo Amplifier

Industry-leading Basic Performance

Industry-leading Level of Servo Amplifier Basic Performance

Speed frequency response of 2.5 kHz is achieved by applying our original high-speed servo control architecture evolved from the conventional two-degrees-of-freedom model adaptive control to the dedicated execution engine. Together with a high-resolution absolute position encoder of 4,194,304 pulses/rev, fast and accurate operation is enabled. The performance of the high-end machines is utilized to the fullest.

Improving Machine Performance with High-performance Servo Motors

Rotary servo motors achieve high-accuracy positioning and smooth rotation with a high-resolution encoder and improved processing speed.

Advanced Servo Gain Adjustment Function

One-touch Tuning

Just turn on the one-touch tuning function to complete servo gain adjustment automatically, including machine resonance filter, advanced vibration suppression control II*1, and robust filter for maximizing your machine performance. This function also sets responsivity automatically, while the real-time auto tuning requires manual setting. Moreover, a new method*2 allows to create an optimum tuning command inside the servo amplifier.

*1.The advanced vibration suppression control II automatically adjusts one frequency.

*2.This new method is available with MR-J4-B/MR-J4W_-B/MR-J4-A with software version of C1 or later.

Advanced Vibration Suppression Control II

The advanced vibration suppression control II suppresses two types of low frequency vibrations owing to vibration suppression algorithm which supports three-inertia system. This function is effective in suppressing residual vibration with relatively low frequency of approximately 100 Hz or less generated at the end of an arm and in a machine, enabling a shorter settling time. Adjustment is easily performed on MR Configurator2.

Robust Filter

Achieving both high responsivity and stability was difficult with the conventional control in high-inertia systems with belts and gears such as printing and packaging machines. Now, this function enables the high responsivity and the stability at the same time without adjustment. The robust filter gradually reduces the fluctuation of torque in a wide frequency range and achieves more stability as compared to the prior model.

Expanded Machine Resonance Suppression Filter

With advanced filter structure, applicable frequency range is expanded from between 100 Hz and 4500 Hz to between 10 Hz and 4500 Hz. Additionally, the number of simultaneously applicable filters is increased from two to five, improving vibration suppression performance of a machine.

Lost Motion Compensation Function

This function suppresses quadrant protrusion caused by friction and torsion generated when the servo motor rotates in reverse direction. Therefore, the accuracy of circular path will be improved in trajectory control used in XY table, etc.

* This function is not available with MR-J4W2-B and MR-J4W3-B.

Super Trace Control

This function controls droop pulse to nearly zero not only during constant operation, but also during constant acceleration/deceleration. The trajectory accuracy will be improved in high rigidity machines.

* This function is not available with MR-J4W2-B and MR-J4W3-B.

A Variety of Functions for Various Applications

* Use a compatible controller.

Tightening & Press-fit Control

Position/speed control switches to torque control smoothly without stopping or changing the speed or the torque rapidly. Load to the machine is reduced, and high-quality molding is achieved for an application where control is switched from position to torque such as Tightening & Press-fit control or insertion of a work, and cap or screw tightening.

* Available with MR-J4-B/MR-J4W2-B/MR-J4W3-B.

Master-slave Operation Function

With the master-slave operation function of MR-J4-B servo amplifier*, the torque of a master axis will be transmitted to slave axes through the driver communication. This enables a torque control operation with the slave axes, using the torque as a command. No additional wiring is required because the torque data is transmitted from the master axis to the slave axes via SSCNETIII/H.

* This function is available with MR-J4-B servo amplifier with software version A8 or later.

Scale Measurement Function

The scale measurement function of MR-J4-GF/MR-J4-B*1/MR-J4W2-B*1 servo amplifiers*2 enables to transmit position information of a scale measurement encoder to the controller when the scale measurement encoder is connected in semi closed loop control.
The data of linear or synchronous encoders are transmitted to the servo system controller via the servo amplifier, achieving less wiring.

*1. This function is available with the servo amplifier with software version A8 or later, but not available with MR-J4W2-0303B6.

*2. Use corresponding servo amplifier (MR-J4-GF/MR-J4-GF-RJ/MR-J4-B/MR-J4-B-RJ) for load-side encoder.

Applicable for Various Control and Driving Systems

Compatible Servo Motors

MR-J4 series servo amplifier operates rotary servo motors, linear servo motors, and direct drive motors as standard*.

* Not all of the servo amplifiers are compatible with all three of these servo motors. For the combination, refer to "Product lines" in the catalog.

1-axis/2-axis/3-axis Servo Amplifiers

For SSCNETIII/H compatible servo amplifiers, 2-axis and 3-axis types are available in addition to 1-axis type, enabling flexible systems based on the number of control axes.

Compatible with Fully Closed Loop Control

MRJ4-GF/MR-J4-B/MR-J4-A servo amplifier is compatible with fully closed loop control system*1. Accurate control of load-side position is achieved*2.

*1. MR-J4-GF/MR-J4-B/MR-J4-A servo amplifier is compatible with two-wire type serial linear encoders. For four-wire type serial and pulse train interface (A/B/Z-phase differential output type) linear encoders, use MR-J4-GF-RJ/MR-J4-B-RJ/MR-J4-A-RJ.

*2. Some models are not compatible with the fully closed loop control system. Refer to "Product lines" in the catalog.

Wide Range of Power Supplies and Capacities

MR-J4-B/MR-J4-A servo amplifiers support 3-phase 200 V AC/400 V AC, 1-phase 100 V AC, and 48 V DC/24 V DC for the main circuit power supply, and the capacity ranges from 30 W* to 55 kW.
For MR-J4-GF, 3-phase 200 V AC/400 V AC is supported. In addition, MR-J4-GF-RJ/MR-J4-B-RJ/MR-J4-A-RJ supports DC power input.

* Servo amplifiers of 30 W is compatible with a power supply of 48 V DC/24 V DC.

Maximum Command Pulse Frequency


General-purpose interface compatible MR-J4-A servo amplifier supports maximum command pulse frequency of 4 Mpulses/s (when differential receiver is used).
When open collector is used, both sink and source inputs are enabled.

Built-in Positioning Function for Simple System

Servo Amplifier with Built-in Positioning Function

MR-J4-A-RJ*1 has a built-in positioning function, enabling positioning operation with point table, program-based, and indexer (turret) methods.
With this servo amplifier, a positioning system is configured without a Positioning module (command pulse). Positioning command is executed by input/output signals or RS-422/RS-485 communication (up to 32 axes). MR Configurator2*2 allows easy setting of the positioning data.

*1. Use MR-J4-A-RJ servo amplifiers with software version B3 or later when using the positioning function.

*2. Use MR Configurator2 with software version 1.25B or later. Be sure to update your MR Configurator2 to the latest version.

Setting position data (target position), servo motor speed, and acceleration/deceleration time constants in point table is as easy as setting a parameter. Up to 255 points are settable for the point table. The positioning operation is performed with a start signal after selecting the point table No.

* Point table can be set with push buttons on the servo amplifier or MR-PRU03 parameter unit along with MR Configurator2.

Create positioning programs with dedicated commands. The positioning operation is performed with a start signal after selecting the program No. The program-based method enables more complex positioning operation than the point table method. Maximum of 256 programs are settable. (The total number of steps of program: 640)

* MR Configurator2 is required to create programs.

Perform positioning operation by specifying equally divided stations (up to 255 stations). The travel distance will be calculated automatically based on the number of equally divided stations set in the parameter. The positioning operation is performed with a start signal after selecting the station position No.
In addition to rotation direction specifying indexer and shortest rotating indexer, backlash compensation and override function are also available.

* Fully closed loop control mode and linear servo motor control mode are not supported by the indexer (turret) method.

New Useful Functions with Positioning Function

New useful functions are added to the positioning function: simple cam function, encoder following function, command pulse input through function, mark sensor input compensation function, and communication functions (MODBUS® RTU, Point to Point positioning, and current position latch function). Apply these useful functions to a wide variety of applications to configure positioning system easily. Use MR-J4-A-RJ servo amplifier with software version B7 or later. These functions are not available with MR-J4-03A6-RJ.

MR Configurator2 enables to create various patterns of cam data. Command pulse or point table/program start signal is used as input to the simple cam. The input command will be outputted to the servo motor according to the cam data.

With the encoder following function, the servo amplifier receives A/B-phase output signal from the synchronous encoder as command pulse, and the input command will be outputted to the servo motor according to the cam data. Setting cam data that matches with the sheet length, a diameter of the rotary knife axis, and the synchronous section of the sheet enables a system in which the conveyor axis and the rotary knife axis are synchronized. Up to 4 Mpulses/s of input from a synchronous encoder is compatible with the servo amplifier.
The command pulse input through function allows the first axis to output A/B-phase pulses which are received from the synchronous encoder to the next axis, enabling a system in which the second and later axes are synchronized with the synchronous encoder.

The actual position of the servo motor is obtained based on the inputs from the sensor that detects the registration marks printed on the high-speed moving film. The servo amplifier calculates compensation amounts and corrects position errors of the rotary knife axis based on those inputs from the sensor so that the film can be cut at the set position.

In addition to RS-422/RS-485 communication (Mitsubishi general-purpose AC servo protocol), RS-485 communication (MODBUS® RTU protocol) is supported. MODBUS® RTU protocol is compatible with function code 03h (Read holding registers), etc.
Controlling and monitoring of the servo amplifier is possible by external devices.

* RJ-45 junction connector terminal block and RJ-45 compatible cable designed for MR-J4-A-RJ are required.

Up to 255 points of Point to Point positioning are enabled when the target position is set in the point table in advance. Rewriting the next target position during a operation is also possible by the communication function.

Based on the data latched by the mark detection function (current position latch*), a target position is compensated by being written in the point table.

* When the mark detection signal turns on, a current position will be latched, and the latched data will be read with the communication function.

Example: Executing positioning compensation when a product is mispositioned by 50 on a handling pallet.
Start an operation by specifying point table No. 1 (target position: 1000).
Communication function (current latch) measures a position gap with the mark detection function and writes the position gap of 50 to the target position in point table No. 2 for compensation during the operation.
After the operation of point table No. 1 is completed with a position gap of 50, start the operation by specifying point table No. 2. The product will be set to the right position.

All-rounder Network with CC-Link IE Field

All-in-One Network

The network is designed to simultaneously handle distributed control, I/O control, and motion control. CC-Link IE Field Network lets you connect field devices such as programmable controllers, I/O modules, high-speed counter modules, servo amplifiers, inverters, and displays, providing optimal network which best fits the needs of the application.
Choose from star, line, or ring* topology suitable for layout of lines and machines.

* The Simple Motion modules are not compatible with ring topology.

All-in-One Engineering Software

This all-in-one MELSOFT GX Works3 covers all aspects of the product development cycle from system design to maintenance - including programming, setting of CC-Link IE Field Network and Simple Motion modules, and adjustment of servo amplifiers.

All-rounder Driving System with CC-Link IE Field

Compatible with CC-Link IE Field Network

MR-J4-GF(-RJ) is compatible with CC-Link IE Field Network as standard.
The servo amplifier is connectable with Ethernet-based CC-Link IE Field Network, enabling high-speed, seamless communication.

Easy Positioning with CC-Link IE Field NetworkVerUP

A combination of a master module and MR-J4-GF(-RJ) allows positioning operation with point table method, not requiring a Positioning module. Just set the point table No. and turn on the start signal, and then the positioning operation will be started. Automatic continuous operation of the next point table is also possible without stopping.

CC-Link IE Field Network Motion Control

A combination of a Simple Motion module and MR-J4-GF(-RJ) enables high-performance synchronous control and interpolation control with simple parameter setting and a start from a sequence program. Speed control and torque control are also possible, suitable for converting machines. In addition, using remote inputs/outputs which are compatible with the synchronized communication function enables a system synchronized with the command cycle of the servo amplifier.

In a single network, inputs/outputs are synchronized with the command communication cycle of the servo amplifier. For example, an input from a synchronous encoder and an output to a printing machine are synchronized in the same network.
CC-Link IE Field Network enables a wide range of Motion control applications.

CC-Link IE Field Network Expanded functions

Automatic calculation of travel distance with parameter setting of the number of stationsVerUP

Indexer (Turret) Method

The indexer (turret) method with rotation direction specifying indexer and shortest rotating indexer is now available in addition to the point table method of the built-in positioning function. The travel distance will be calculated automatically based on the number of stations and the number of gear teeth on the motor and machine sides set in parameters. The positioning operation is performed with a start signal after the station position No. is selected.

Indexer (Turret) Method

Creating a cam with the built-in cam function of the servo amplifierVerUP

Simple Cam Function by a Combination with a Master Module

With a master module such as RJ71GF11-T2, the simple cam function enables software-based synchronous control as an alternative to mechanical control using a cam mechanism. With this function, various cam patterns can be created with MR Configurator2. The point table data is used as input to the simple cam, and commands are outputted to the servo motor based on the cam data. With MR-J4-GF-RJ, a synchronous encoder can also be inputted to the simple cam.

Simple Cam Specifications

Item Description
Memory capacity Storage area for cam data 8 Kbytes (non-volatile memory)
Working area for cam data 8 Kbytes (RAM)
Number of registration Maximum 8 (depending on cam resolution and coordinate number)
Comment Maximum 32 single-byte characters for each cam data
Cam data Stroke ratio
data type
Cam resolution
(Maximum number of registration)
256 (8), 512 (4), 1024 (2), 2048 (1)
Stroke ratio -100.000% to 100.000%
data type
Coordinate number
(Maximum number of registration)
2 to 1024
Example: 128 (8), 256 (4), 512 (2), 1024 (1)
Coordinate data Input value: 0 to 999999 Output value: -999999 to 999999
Cam curve 12 types (constant speed/constant acceleration/5th curve/single hypotenuse/cycloid/distorted trapezoid/distorted sine/distorted constant speed/trapecloid/reverse trapecloid/double hypotenuse/reverse double hypotenuse)

When more advanced cam control is required, such as synchronous control and cam auto-generation, use RD77GF or QD77GF Simple Motion module as a master module.

Encoder Following Function, A/B-phase Pulse Input Through Function, and Mark Sensor Input Compensation FunctionVerUP

Simple synchronous control with MR-J4-GF-RJ

With the encoder following function, the servo amplifier receives A/B-phase output signals from a synchronous encoder as command pulses to drive the servo motor. Together with the simple cam function, setting cam data corresponding to sheet length, a circumference of a rotary knife axis, and synchronous section of the sheet enables a system having a conveyor axis and a rotary knife axis synchronized.
The A/B-phase pulse input through function allows the first axis to output A/B-phase pulses which are received from the synchronous encoder to the next axis, enabling a system in which the second and later axes are synchronized with the synchronous encoder.
The mark sensor input compensation function corrects the cam position of the rotary knife axis when there is a deviation between the target and current positions. For example, if expansion or contraction of a sheet causes such position deviation, the cam position will be corrected for proper processing.

When high-accuracy synchronous control is required, use RD77GF or QD77GF Simple Motion module as a master module, and execute motion control.

Achieving Category 4 PL e, SIL 3VerUP

Higher safety level with a combination of MR-J4-GF-RJ and MR-D30 functional safety unit

Category 4 PL e, SIL 3 is achieved when the safety signals are inputted directly to MR-D30 functional safety unit*3. The safety observation function is operated on the MR-D30 by parameter setting, and therefore expansion of the safety observation function is possible independent of controllers.

Preventive maintenance by monitoring operationPatent pending VerUP

Failure Prediction Function

A failure prediction function is newly available for predictive maintenance, helping you detect signs of performance degradation in a machine prior to failure without a periodical inspection of frictions and vibrations.
With this function, the servo amplifier detects and predicts aging-related changes in a machine performance, based on the frictions and vibrations monitored by the machine diagnosis function, and informs the maintenance time with a warning. Periodical programs and determination values created for maintenance of each machine is no longer needed.

The servo amplifier also predicts machine failure based on the total travel distance of the servo motor. The maintenance time will be informed with a warning when the total travel distance exceeds the failure warning limit set by you. When the limit is set to the rated life of a ball screw or bearing, preventive maintenance can be executed according to the actual machine operation.

The failure prediction function is available with MR-J4-GF servo amplifiers with software version A3 or later. The failure prediction function does not guarantee that a warning is outputted before every failure. If the machine receives an external impact, the machine may break down before a warning is given by the failure prediction function. When you need to know the machine failure more precisely, it is recommended that you compare the friction and vibration values of when the warning was given and of when the operation was started. The friction and vibration values are monitored by the machine diagnosis function.

Efficient development and reduction of maintenance time with PLCopen Motion Control Function Block

PLCopen® Function Block

PLCopen Motion Control Function Block having standardized interface offers the following advantages:

  • ・ Saving time and cost by reducing the burden of programming
  • ・ Reducing maintenance time as it is easy to understand the programs even for non-programmers

[Example: absolute positioning]
Equipment: R04ENCPU + MR-J4-GF
Function block: MC_MoveAbsolute + J4GFIO

Positioning operation is executed based on the target absolute position of the specified axis.

PLCopen Motion Control Function Block is available for free download. Contact your local sales office for more details.
PLCopen and related logos are registered trademarks of PLCopen.

Protecting your data - parameters, point table, and simple cam dataGOTDrive

Backup/Restore by GOT

Backup the data such as parameters, point table, and simple cam data of the servo amplifier onto the GOT's memory card or USB memory. The backed up data in the GOT can be restored back to the servo amplifier.
Sequence programs and data from other modules such as FR-A800 inverters can also be backed up and restored by GOT via CC-Link IE Field to protect the whole system.

High-response Servo System Achieved with SSCNETIII/H

Three Times Faster Communication Speed

Communication speed is increased to 150 Mbps full duplex (equivalent to 300 Mbps half duplex), three times faster than the conventional speed. System response is dramatically improved.

Deterministic and Synchronized Communication

Complete deterministic and synchronized communication is achieved with SSCNETIII/H, offering technical advantages in machines such as printing and food processing machines that require synchronous accuracy.

Cycle Times as Fast as 0.222 ms

Smooth control of machine is possible using high-speed serial communication with cycle times of 0.222 ms.

No Transmission Collision

The fiber-optic cables thoroughly shut out noise that enters from the power cable or external devices. Noise tolerance is dramatically improved as compared to metal cables.

Dramatically Reduced Wiring

The SSCNETIII/H Head module allows the controller to connect remotely with various modules (I/O, analog, high-speed counter, etc.) via SSCNETIII/H. This results in reduced wiring since the Motion controller receives the I/O and analog I/O signals directly from the servo amplifier side.

Long Distance Wiring up to 3200 m

Long distance wiring is possible up to 3200 m per system (maximum of 100 m between stations × 32 axes). Thus, it is suitable for large-scale systems.

* This is when all axes are connected via SSCNETIII/H.

Central Control with Network

Large amounts of servo data are exchanged in real-time between the controller and the servo amplifier.
Using MELSOFT MR Configurator2 on a personal computer that is connected to the Motion controller or the Simple Motion module helps consolidate information such as parameter settings and monitoring for the multiple servo amplifiers.

Compatible Products Connected in a Same System

SSCNETIII/H and SSCNETIII compatible controllers support the use of SSCNETIII/H and SSCNETIII compatible servo amplifiers together in a same system.

* When the SSCNETIII compatible products are in the system, the communication speed is 50 Mbps interactive, and the function and the performance are equivalent to those of MR-J3.