Expand alarm reporting to indicate reading errors.
When doing the alarm scan, if reading the device results in an error, an alarm is posted but doesn't indicate it was due to an error. This issue proposes that extra information be provided.
Bits 11 and 12 in the alarm block header currently indicate whether the alarm is good or in alarm high or low. Instead, we propose that the two bit form an enumeration field where:
|1||In alarm: Low|
|2||In alarm: High|
|3||In alarm: Reading error|
The ACNET status returned by the bad reading should also be placed in the ERP parameter field.