One of the benefits of an Internet-enabled CNC is the potential to reduce the cost and delay associated with service calls, In many cases a machine may not be down because of a mechanical or hardware failure, but instead it may be a programming or parameterizing problem that causes a machine to stop. Problems of this type can often be addressed remotely. Communicating with the CNC across the Internet, using security protocols to protect against authorized access, offers a readily available way to perform this remote service.

But providing the CNC with an Internet connection opens up new possibilities not just for the CNC supplier's service department, but also for the service department of the company using the machine. Thanks to the Internet access, the CNC can be equipped to send e-mails automatically in response to faults or other control-related events. The CNC can even send text alerts via SMS (Short Message Service) to mobile phones.

CNC technology supplier Siemens (U.S. office in Elk Grove Village, Illinois) has developed software called "@Event" for exactly this purpose. The software links a Siemens Sinumerik control to a commercially available e-mail program such as Microsoft Outlook Express. The control can then send e-mails to various addresses selected by the user in response to specific alarms.

The software runs on Windows NT. For a given CNC alarm, the software searches through a pre-configured list for the receivers associated with that alarm. It then establishes the link to the e-mail server and sends the receivers the appropriate email or SMS message.

E-mail messages can contain file attachments, so a log or trace file indicating operator actions or states preceding the fault can go out with the message. To assist quick troubleshooting, all of the relevant machine data can also be sent as a sort of identity card for the machine tool.

Other options for defining how the e-mail or SMS messages are sent are also available. For example:

* Every alarm can be transmitted as a separate message, or all simultaneous alarms can be grouped into a single message.

* A complete list of alarms can be sent cyclically, at a predefined interval.

* Messages can be sent only when an alarm occurs, or they can be sent in response to every further status change after that alarm.

The user also has the option to decide which alarm sources trigger any message at all.

Associating alarms with distinct receivers can allow all alarm messages relating to the control to be routed directly to a system specialist at a remote location for immediate analysis. Meanwhile, alarm messages that indicate mechanical faults can be sent to a local service technician, perhaps as an SMS message to a mobile phone, while these same messages are also sent via e-mail to a production manager's PC.