Flow conditions status and data quality
- Last UpdatedApr 24, 2025
- 2 minute read
The flow conditions status and data quality for each operating point sample are recorded as part of the operating point history for a compressor.
Flow conditions typically represent the state of a recycle valve, but may also represent some other relevant quantity. Flow conditions are represented as having four possible states. Either analog or status input can be used to provide the Compressor Performance Monitoring (CPM) application with flow conditions for a compressor. A status input may represent the state of a recycle valve (OPEN, CLOSED, SEQUENCE, or ERROR.) An analog input may represent the open percentage of a recycle valve, thus requiring the definition of four ranges to relate to the four available states. For example, 0-5%, 6-39%, 40-60%, 61-100%.
The data quality of the operating point is derived from the x- (flow) and y- (head pressure) values. Supported data qualities are shown in table below, in order of priority. For example, if the x-value was in the manual state and the y-value was normal, the data quality of the operating point - the x-value and y- value combined - would be manual.
|
Data Quality |
Description |
|
Alarm |
The operating point was determined to be in an alarm state by the CPM application. The operating point is to the left of the surge control line. |
|
Off-scan |
Either the head pressure (y) or flow (x) value was not recently scanned from a Remote Terminal Unit (RTU) /Programmable Logic Controller (PLC) or calculated by an external program. The flag.fresh flag of one or both values is not set. |
|
Manual |
Either the head pressure (y) or flow (x) value was manually set. The flag.manl flag of one or both values is set. |
|
Unknown |
The data quality of the operating point could not be determined by the CPM application. |
|
Normal |
None of the above conditions are true. |
In the case of manual and off-scan data qualities, the data quality is reflected directly on the compressor.