Health care for encoders

摘要

Embedded microprocessors in intelligent rotary encoders communicate more than just position. Many also send status reports on their condition along with a notice of any detected faults. The amount and type of diagnostic information available from encoders typically depend on how they communicate. Various communication protocols provide different types and degrees of information, Most encoder protocols generate several levels of diagnostic alerts using warnings or alarms. Warnings indicate encoder conditions could cause errors or failures. Excessive LED current is one example. Higher-than-normal current reduces an LED's life expectancy, leading to failure of the LED and encoder. Alarms, on the other hand, alert operators that there has been a malfunction or failure that might lead to incorrect position values. Actual failure of the LED or an encoder rotating faster than its rating are typical examples. When reporting problems some encoders provide dedicated alarm outputs while others set alarm or warning bits in their position data.