Curve set records

Each compressor (reciprocating or centrifugal) has characteristics that are accounted for in a unique set of speed vs. efficiency curves provided by the manufacturer.

Curve set data must be stored in the RealTime database (RTDB), as operating point data collected and maintained for a unit is relevant only with respect to the curve set that is associated with the unit when the data is recorded.

Note: Because performance curve data is not maintained historically, you can only display operating point data in easy eXtended Operator Station (ezXOS) if the curve set that is currently associated with the compressor is the same one that was in use when the operating point was recorded.

Compressor Performance Monitoring (CPM) tracks which performance curve set is associated with each recorded operating point and logs all changes to curve set data as events. You may need to assign a new curve set to a compressor if:

The compressor wheel for a centrifugal compressor is changed due to maintenance or flow capacity requirements.

The performance curve becomes inaccurate over time and requires adjustment. For information about defining curve sets, refer to Configure a curve set record.

You can view examples of curve sets in the "Sample Rated Speed Curve" figure above.