The A700 Variable Frequency Drive:
"I can't believe it's not Servo!"

The A700 is a high performance version of Mitsubishi Electric's F700 drive, and is replacing the popular A500(L) series. It features many of the special technologies originally developed for Mitsubishi Electric servo drive products, such as adaptive auto-tuning that automatically compensates for changes in load inertia. The result is smoother operation, less downtime and ultimately, lower operating costs.

The key to the increased performance is Mitsubishi's Real Sensorless Vector (RSV) motor control system, which provides unequalled dynamic performance, ensuring a wider speed range, smoother operation and lower motor currents than ever before. RSV starts with a highly accurate motor "map", obtained during an auto-tune procedure which applies alternating voltage to the motor and determines critical motor characteristics. At the heart of RSV is the Adaptive Flux Observer system which compares actual motor behavior during operation with the theoretical model. Instead of a response to a change in load or speed being fixed, any variations between the theoretical and the actual motor response measured in operation are analyzed by the Flux Observer, which constantly refines the motor map as speed and load conditions change.

The advanced performance provided by the A700 series makes it possible to support a wide range of variable speed and line control applications such as conveyance, chemical machines, winding and printing machines. Improved flexibility allows users to tailor their VFD to meet their application requirements.

Capability

The A700 comes in sizes ranging from 3/4 HP to 700HP, to cover a wide variety of applications. Mitsubishi Electric's new RSV algorithm gives 200:1 speed range for closed or open loop applications, with 200% torque at speeds as low as 0.3Hz. The A700 uses servo-drive technology to compensate automatically for changes in load inertia to ensure smooth and consistent operation. This gives the drive a 300 radians/ second speed response for lightning fast reaction to sudden load changes.

Control

Point-to-point Positioning Control comes as standard for postion control, but the A700 can take pulse train inputs for accurate Speed Control, or use the Sensorless (Open Loop) Torque Control, which can hold torque at zero speed, for wind/unwind applications. Additionally, the A700 includes an embedded PLC for fully programmable control and customized applications. Using the GX Developer software package, the user can customize drive control and I/O based on internal variables such as timers, counters or user parameter settings.

Communications

The A700 comes with two RS-485 serial ports and one USB port for network communications and software configuration using FR-Configurator. There are also add-on communications modules available for the A700's three option ports. Supported communications protocols include:

• Profibus-DP
• LonWorks
• DeviceNetTM
• CC-Link
• EtherNet/IPTM
• Modbus TCP/IP
• Mitsubishi RS485
• Modbus RTU
• SSCNetIII
• Metasys N2

The communications networking allows the A700 to be part of an overall Remote I/O system as well, with the status of all I/O readable over the network, including analog information. Drive outputs and hard relays can be "forced" over the network as well, or operated independently via the PLC function.

Robust Package

• Bigger Braking Circuit - Eliminates the need for external brake units on drives up to 30 HP
• Power-Down Braking - Keeps the motor under control even if supply power is lost
• Integral Radio Filter - Limits radio noise to meet EC Directive 89/336 (EN 61800-3) -- all drive sizes
• On-line Auto-tune Feature - Compensates for motor temperature changes
• UL Type 1 Construction - Allows direct conduit mounting outside of an enclosure, and is available up to 30HP without option (ND based). Larger capacities available as an option.
• Sink/Source Logic selectable - For flexible wiring
• Removable Control Terminal Block - For easy maintenance

Options

Advanced Keypad Option (PU07)
• 24 button keypad
• Alphanumeric Display (LCD)
• Upload / Download Parameter sets
• Store up to 3 sets of drive data
• Battery option allows data transfer without powering up the drive

Three Option Ports - Flexible choices allow user to select application specific options such as DeviceNetTM, Ethernet I/PTM, ControlNetTM, encoder, expanded I/O, and more.