Condition Monitoring For Embedded PCs

Embedded computer systems are often used in stand-alone systems that must operate reliably for long periods without intervention. For this they are constantly observed — their loss can usually not be tolerated. To monitor their operational state, so-called condition monitoring can be used. With condition monitoring, the module’s key parameters can be proactively observed and, when required, preventive maintenance can be initiated.

Condition monitoring not only includes the current operating state, but also keeps historical records of past conditions. The device’s ambient temperature may serve as an example: whether it exceeded or fell below the permissible limits is an essential criterion for the electronics’ expected life time.

It is also desirable to know about the actual consumption data of the system. These include the current supply voltages and current. Having these numbers available, one can make firm statements about the state of the system, which are well above a simple "Go / No go” statement.

When doing error analysis, not only records of the environmental conditions are important, but also details of the board’s up-time or of any previously occurred errors that have resulted in the restart of the system. It is also interesting to know the entire accumulated run time of the system. With these figures, its remaining service life can be estimated accurately.

LiPPERT Embedded Computers’ current boards all feature built-in support for such functionality, the LiPPERT Embedded Technology Management (LEMT). The LEMT functions are implemented within the in System Management Controller (SMC), a micro controller, which is necessary anyway. It communicates via the SM bus with the chipset of the COM module and thus obtains all relevant data. The SMC has built-in flash and RAM areas, which are made available to the user by LEMT functions. The flash area is divided in manufacturer and user specific part. The manufacturer part is used to store pertinent information about the device, such as part number, BIOS revision and the like. The 1 kB user flash is available for persistent data of the application. Additionally, there is a 128 byte one-time-programmable region of flash memory for critical data like security keys that may not be changed.

All these features are accessed using the user interface program provided by LiPPERT. However, LEMT functionality can also be integrated into the user’s application. A source code interface is available, providing easy access to LEMT’s functions.

One last feature worth mentioning, even though it is does not provide status information to the user: some boards even include Fail-Safe-BIOS. If a BIOS update fails due to a power failure during the process, the board ends up without BIOS and does not work any longer. In consequence a technician must repair the unit on-site. The Fail-Safe-BIOS eliminates this risk and can thus minimize the system downtime. A secondary BIOS automatically takes over when the first one is corrupted.

A white paper with a detailed description of LEMT functions and implementation is available on LiPPERT’s website. (www.lippertembedded.com/whitepapers.html)

LiPPERT Embedded Computers, Inc.
5555 Glenridge Connector
Suite 200
Atlanta, GA, 30342

tele: 404.459.2870
fax: 404.459.2871