Checkout check keeps foodstore tills ringing

By MICHAEL FOREMAN

A power blackout can wreak havoc in a business that has become dependent on computers, but some are more vulnerable than others.

Willie Williamson, account manager at Auckland power protection specialist Dataguard, says supermarkets rank highly on the casualty list when the lights go out.

Most supermarkets use backup generators if the power fails, which saves food in the freezers from thawing. But the PCs at the checkouts will still have to be rebooted.

A large store can turn over $70,000 to $80,000 an hour, so losing the checkouts for even a few minutes is significant - and inconvenient to customers.

"You can't do a damned thing at the checkouts without power," Mr Williamson says.

"It's the barcode environment that's done that - nothing is priced any more. Either you've got to let the customers walk out without purchasing the products or you can try and guess what the total comes to."

Neither option seemed attractive to one Dataguard client, Woolworths, which is installing what is believed to be New Zealand's largest network of remotely managed uninterruptible power supplies (UPS).

When the installation is complete, UPSs in 94 supermarkets will be linked through the internet to Dataguard and Woolworths' Manukau City head office.

The system allows either company to check that the UPSs are working properly and monitoring any power disturbances.

We visited Dataguard's Mairangi Bay offices, where business manager Paul Jeffries demonstrated how the system worked.

Mr Jeffries said it took around four months to perfect the software, which consists of code written by the German UPS manufacturer, running on top of Tivoli Systems' NetView network management package.

Under the terms of its five-year contract with Woolworths, Dataguard is responsible for all UPS maintenance so it is important the company is aware of any problems.

Now Mr Jeffries can instantly assess the integrity of the power supplies in the network by looking at a single screen, which displays icons representing Woolworths stores grouped into arbitrary regions.

If an icon is green then all is well, if it is yellow then at least one UPS is experiencing a problem, and if it is red then all the UPSs within the region are down.

Clicking on the regional icon brings up a similar display showing individual branches. Any having problems will be shown in red.

On the day we visited, the icon for the northern South Island was showing yellow, which turned out to be the result of a faulty communications card at one branch.

When problems such as this occur, the system also sends a text message to the mobile phones of the relevant Dataguard people.

"We can know about a problem before the store does," he said.

Apart from a couple of blackspots such as Auckland's North Shore Bays, the reliability of power supply across the country had been surprisingly good, said Mr Jeffries.

"But then we haven't gone through a bad winter yet. When the water level at Lake Taupo gets low we will expect to see some problems."

So far, blackouts or low power incidents serious enough to put the supermarket PCs on to battery power have occurred around three or four times a month.

In all cases the UPS, with a typical battery run time of at least two hours, kept the stores' PCs running until the problem was fixed.

More common are voltage fluctuations which last a second or two. They are caused by nearby compressors, hospital equipment, or the power company switching transformers. Supermarkets are especially prone to problems because of the large amount of refrigeration equipment they have.

The UPS shields the PC from these problems by supplying it with a steady output voltage.

But anything below 200 volts or above 260 volts can cause data loss or damage to unprotected hardware, says Mr Jeffries.

"A very high transient surge can literally destroy your PC," he said.

Mr Jeffries clicked on a few branches to demonstrate

At Timaru, where the UPS was delivering a steady 232 volts and battery temperature, which can be an early indication of trouble, was stable at 31 degrees.

This UPS was running at 22 per cent of its capacity and should the worst happen, the store had 244 minutes of battery run time before the checkout went down.

As well as monitoring the power supplies, the remote management system allows Dataguard to test them.

"Every two to three months we drop them onto the battery and pray that they come back again," joked Mr Jeffries.

With an eerie ease, he switched off the mains to a PC hundreds of kilometres away in Timaru.

"There, it's running on battery. The mains has been turned off and the store wouldn't know anything about it."