Honeywell SmartLine ST 800 User Manual page 42

The display will calculate 0-100 %Flow from the Differential Pressure and then scale this to 0
to 2500 gal/h.
Note that the Square Root calculation is referenced to the LRV and URV settings of the
transmitter and it uses the LRV and URV to calculate the %DP input into the Square Root flow
algorithm. For normal flow applications, it is assumed that the LRV is set to zero and that zero
pressure equals zero flow. If the LRV is less than zero, the Square Root calculation will calculate
the flow as bi-directional flow.
3. PILD Factor Value Display
The PILD Factor can be configured as screen PV selection when the PILD option is enabled.
It will not display units and square root indication while displaying in large, trend or bar formats.
The large PV format provides the current Up Limit and Down Limit values. The PILD Factor
value is present only when PILD is enabled and while in Monitoring mode. Otherwise, the value
will be replaced by a message indicating PILD is disabled or in Training mode.
The trend format provides two dotted horizontal lines on the trend chart to indicate the Up Limit
and Down Limit values.
4. Field Calibration for Alternate Ranges
All ST 800 transmitters are precisely calibrated at the factory and can be calibrated at up to
three sets of LRV and URV span ranges that can be specified when ordered.
Span ranges other than those calibrated at the factory may be configured and users may need
to verify accuracy at those ranges using their own accuracy standards.
User calibration can be performed at two points within the span range of LRV to URV. It is
critical that the pressure standard used for calibration at these two points should be certified
to at least twice the pressure transmitter's accuracy. This is to prevent misleading results
that can occur when pressure standards are used that are considered accurate but in reality,
are worse than the accuracy of factory-calibrated transmitters.
ST 800 Pressure Transmitter User's Manual
32 Revision 15