COPP uses a data format where some values mean data quality. The system sets all bytes in a floating-point to FF on startup. The bit pattern is “Not A Number”, that means “invalid” data in COPP. COPP only uses unsigned integers, where the highest values only can indicate “invalid” data. An example is an 8-bit unsigned integer that allows values from 0-255. COPP uses the values 253, 254, and 255 for data quality, so you can use the values from 0-252.

Another example is an analog input that measures a value outside its input range. In that case, the data gets one of three “invalid” indicators.

Data Quality can be:

• Valid
• Negative_restricted
• Positive_restricted
• Invalid

To sum up, P-NET sends data quality. When data is corrupt – for example, when there is no answer from P-NET – data is Invalid.