This module calculates flow from a differential pressure input. It is applicable for use with pitot tube sensors that are commonly provided with variable air volume terminal units.
This module supports automated offset (that is, zero flow) calibration of the differential pressure sensor input. The application can take advantage of this by closing the dampers or equalizing the intakes of the differential pressure sensor input and then setting the Autocalibrate Now input temporarily to True.
As long as this input is True, the module calculates the average Autocalibration Offset that would cause the flow calculation Effective dP to equal zero. This average is done recursively using the EWMA function that does a simple average for the first 1,000 samples. Typically, the Autocalibrate Now input is set True for only 5 to 10 seconds at a time and must reset to False by the connected source.
You cannot view or modify the modules in this group’s logic.