Class B

Modern appliances are mostly electronically controlled. Electronic controls enable higher efficiencies, additional functionality, and an improved user experience. But what happens if something goes wrong? IEC 60730 addresses the safety of electronic controls in appliances. This standard is also referred to by other standards for safety-critical devices, for example, IEC 60335. Currently, IEC 60730 is mandatory for appliances sold in Europe, and widespread adoption is likely.

IEC 60730 Annex H defines three classes of control software for appliances:

Class A - Control functions which are not intended to be relied upon for safety of the equipment.
Class B - Software that includes code intended to prevent hazards if a fault, other than a software fault, occurs in the appliance.
Class C - Software that includes code intended to prevent hazards without the use of other protective devices.

For an appliance to comply with the Class B requirements, the control software must detect and handle faults for system components. For a customer wishing to certify a product in accordance with Class B requirements, Microchip offers a Class B library for tinyAVR^® 1-series. This library implements the tests needed to be in compliance with Class B and can reduce development time and cost for the customer.

Tests are done on CPU registers, program counter, frequency, CRC, interrupt handling and execution, clock, SRAM, Flash, and EEPROM, and peripherals such as ADC, DAC, and WDT.

For more information, refer to Guide to IEC 60730 Class B Compliance with tinyAVR 1-series.