A new level of simplicity for drive programming

Hitachi's DriveManager emulates Hitachi's existing DOP and DRW hand held programming units, but with the convenience of being able to program drives at a desktop with a full size monitor.

Only a short time ago, the installation and commissioning of an AC variable speed drive was a job best left to the experts.

Now, some new software for AC inverter drives makes them so simple to use, that plant engineers can fit them and tune them for most applications without training.

There are a number of factors that have simplified drive installation - but most notably it is increasingly powerful electronics and better software.

Paradoxically, the more sophisticated the inverters themselves have become, the greater the opportunity to make the drives simple.

Some of the new breeds of inverters have become almost plug and play - particularly the sensorless vector types that usually feature some form of automatic tuning these days.

What most new inverters, at least the better ones, all share is highly advanced microelectronics that enable fast processing and control.

These new breeds of drives use advanced control technologies such as sensorless flux vector (where the motor is more tightly controlled but without the need for closed loop feedback devices such as encoders, resolvers or tachometers), fuzzy logic, PID control and so forth.

All of this increases the functionality of the standard drive and the number of parameters that can be adjusted to suit a broad range of applications.

One of the problems faced by users of all sorts of industrial products and equipment is the apparent relish with which manufacturers call a "spade" a "manual implement for soil displacement and removal".

Only the most foolhardy of consumer electronics companies would refer their users to an audio level adjustment potentiometer when they mean the volume knob! Drives makers, while by no means the worst culprits, are far from blameless in this respect.

How many plant engineers are really comfortable setting the e-therm, base voltage and so forth? What do these parameters do? For that matter what do the other 150 parameters one is likely to find in a modern AC inverter do? Most drives have keys through which programs can be entered at the drive.

Many models have abbreviated keypads that look simple enough, but involve paging through menus of selections and usually require reference to the operating manual for two reasons - one, to check what the abbreviated references that appear on the screen relate to, and two, to check what parameters affect what functions of the drive.

When setting up a tricky application, such as a lift or hoist for instance, this may not be as easy as first appears.

It's an issue that HID Limited has spent many man years addressing.

As the drives software development partner for Hitachi, HID's programmers have had to consider not only how to make drives even easier to program, but also in such a way as will be relevant in a global market.

What the company has come up with is a new suite of software that allows easy programming and diagnostics for any of the Hitachi inverters.

For the reasons above, many drives are set up remotely using a portable programming unit, if one is available, and sometimes via a PC that can download programs to the portable unit.

In most cases, the hardware is dedicated to the drive.

One of the things that HID was aware of when developing the new Hitachi software, was that most off line programming solutions merely translated exactly what is on the drive into the programming software.

In other words they didn't really make life any easier.

Moreover, programs could only be tested once loaded into the drive.

Hitachi's DriveManager suite of programs is evolving into a very powerful set of tools for all levels of drives installers.

The first program developed was called DOP Plus and runs within Windows 3.11, 95, 98 and NT on any IBM-compatible PC.

Essentially, the software emulates Hitachi's existing DOP and DRW hand held programming units, but with the convenience of being able to program drives at a desktop with a full size monitor.

The screens within the software have been arranged to provide users with the interactivity and intuitive operation of the Windows environment, but also give on screen views of all the DOP screens available.

From the toolbar, users can load data, select printing, text saving and writing EEPROM data to disk.

Because the programming is in text files, the system is ideal for new users of drives since there is no need to have access to or knowledge of inverter address codes.

There are in-built help screens for all function parameters and an automatic quick function parameter selection facility.

The software is able to identify by automatic detection, the inverter range being programmed and can also save and load the inverter set up to disk as well as be printed out.

The current inverter set up can be compared with the set up in a file - a particularly useful feature when trouble shooting or retrofitting drives.

The latest DOP Professional program has joined the initial DOP Plus software.

DOP Professional is an off line programming tool suitable for Hitachi drives.

Apart from all the features of the DOP Plus solution, the DOP Professional also includes a print out that is grouped to ease parameter searching, and multi-lingual capability.

To set up a drive using DOP Professional is simplicity itself.

The opening screen gives the initial choice of parameters, simplified into tabbed menus.

Default settings are included for each parameter and these change colour if the value is altered - a useful feature if checking the program later to see what has been changed.

One of the best features of the software is the application wizards provided.

If the user is new to drives, but knows it is a conveyor application for instance, there is a conveyor specific set of defaults that in most cases will be suitable, together with a set of variables that apply specifically to conveying applications.

Once the program has been written, it can be saved to disk for future reference.

Now comes a really novel development.

The program can be tested within the software using a "virtual inverter".

This simulation shows all the values that have been entered, exactly as they appear on the display screen of the drive itself, plus the terminal assignment is verified by showing graphically as each terminal is energised.

Another unique feature of the new software is the incorporation of "virtual meters" that show speed and current within the inverter.

This feature can be used for on line monitoring when connected to the drive.

Data for diagnostics and trending is collected from the drive and plotted on curves that can be exported to MS Word or as a.CSV file straight into MS Excel to create tables of values that can be subsequently plotted as graphs, charts or histograms.

The auto tuning function of the sensorless flux vector drives can also be controlled within the new DOP Professional software on line.

The user simply selects the SLV option from the top menu bar within the main window.

Even auto tuning is much quicker using the DOP Professional program.

The DOP Professional also accommodates Windows CE so that any compatible palm top computer can be used to download programs on site.

This not only means a more powerful portable tool can be used, but there is no need for dedicated hardware.

There is a Windows to Windows CE conversion within the software that enables programs to be down loaded or up loaded as required.

This tool also enables real time analysis of the actual drive if required by plugging in the palmtop while the actual drive is running and then observing and collecting the data.

Another package within the DriveManager suite is the SRW Simulator software which emulates Hitachi's existing SRW hand held programming unit, but with the convenience of being able to program offline.

This program is less powerful than the DOP professional, but suits some experienced users that merely wish to download off line programs to a drive.

From the toolbar users can load or save the Inverter program to disk, print the setup and the programming uses the same references as the standard keypad.

The software also provides useful documentation, which may be needed by non users of the software.

The software is able to identify by automatic detection, the inverter range being programmed which will prevent the incorrect setup being downloaded.

The biggest growth in the use of AC inverters tends to come from the lower power ranges, say up to 7.5kW.

It is in these growing markets that drives technology is probably least well understood.

For this reason, within the Hitachi Drive Manager suite is a package called QuickStart.

QuickStart is a very simple menu driven Windows based system that requires users to merely enter a few parameters into predefined boxes on screen.

Once they have set up the speed and run options, they simply add the maximum frequency, acceleration and deceleration rates using slider bars and then complete the set up by selecting the internal speed parameters as appropriate.

To load the program to the drive they simply click on "download to the inverter".

Existing programs can also be downloaded from the inverter for editing with the QuickStart program with a single on screen click.

All that is needed to take advantage of QuickStart is an inexpensive communications adaptor that connects the PC to the inverter.

Global Software Support is provided by a dedicated web site www.drivemanager.com where registered users can access free downloads and upgrades.

The developments for the Hitachi drives take programming into a new level of simplicity, but it will not end there.

Stephen Scales of HID is very focused on where programming of all sorts of industrial equipment must head.

"Some engineers might not even fully appreciate the significance of the acceleration and deceleration ramps in a drive, or the internal speed parameters," states Mr Scales, "so we are looking at ways to simplify setting to the same level of, say, most modern domestic appliances with simple selections based on the application".

For example, in future the drive software may give an option simply labelled "conveyor", with the next sub set of selections being for whether the conveyor has a stable load such as boxes, or a load likely to topple, say, bottles.

The software will do the rest.

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