Mitsubishi launches 'next-generation' servo drives
Mitsubishi Electric has launched its next generation of servo systems, comprising the Melservo MR-J4 series of servo amplifiers with associated positioning units, motion modules and integrated motion control systems.
The series represents a significant advance in servo system technology and provides benefits to machine builders and end users, according to the company. Target 'process' applications, it says, include high-accuracy filling and dosing applications in the food and pharmaceuticals industries.
The update on the J3 series, launched back in 2004, incorporates a range of functions that are intended to boost performance while minimising the time-consuming effort of engineering and setting up servo systems.
The MR-J4 series features single-, dual- and triple-axis amplifiers for improved economy, greater energy efficiency and reduced panel space requirements. The servos can all operate with rotary, linear and direct drive motors, and so simplify the system-building process.
According to Mitsubishi, engineering and commissioning time is drastically reduced thanks to the “one touch” auto tune function, which matches the machine mechanics to the servo system in a single operation. This function operates in real time and is dynamic, so if the machine conditions change over time, the MR-J4 system tuning automatically adjusts.
Covering the range from 0.1kW to 55kW, MR-J4 servo amplifiers are available in two versions. The MR-J4A provides analogue and pulse train connections and is designed for conventional control systems and for speed, torque and closed-loop position control.
The MR-J4B comes with connectivity to Mitsubishi’s SSCNETIII/H high performance servo network, meeting the needs of integrated automation systems where complex multi-axis motion control is required. S
SCNETIII/H control information is delivered over a duplex 150Mbps fibre optic bus, which is said to simplify connection and commissioning and permit synchronous coordination of up to 96 axes. Both versions of the amplifier come with built in local I/O for interfacing with signals such as over travel limits and print mark registration.
The MR-J4 amplifiers also include a “life diagnosis function” which monitors the condition of the amplifier at a component level and notifies the user of any degradation in its operation. This feature also has the ability to recognise changes in machine dynamics such as increased vibration and increased motor torque.
The servo motors are fitted with 22-bit absolute encoders as standard, corresponding to more than four million pulses per revolution. This, claims Mitsubishi, outperforms the accuracy of other servo motors on the market by four times and so provides "excellent true-running characteristics and maximum positioning accuracy."
A Mitsubishi release further claims: "Combined with the processing speed of the MR-J4 servo amplifiers and their 2.5kHz frequency response plus inbuilt vibration suppression filter, the result is vastly improved machine performance, with minimised positioning times, reduced cycle times and greater throughput."