4-9
Device Software Functions
DETAILED SETUP
Pulse Output Scaling
The pulse output scaling equates one transistor switch closure pulse to
a selectable number of volume units. The volume unit used for scaling
pulse output is taken from the numerator of the configured flow units.
For example, if gal/min had been chosen when selecting the flow rate
unit, the volume unit displayed would be gallons.
NOTE
The pulse output scaling is designed to operate between 0 and 1000 Hz.
The electronics will not accept a conversion factor that would result in a
pulse frequency outside that range. The minimum conversion factor
value is found by dividing the upper range value (in units of volume per
second) by 1000 Hz.
When selecting pulse output scaling, remember that the maximum
pulse rate is 1000 Hz. With the 110 percent overrange capability, the
absolute limit is 1100 Hz. For example, if you want the
Model 8712C/U/H to pulse every time 0.01 gallons pass through the
flowtube, and the flow rate is 1000 gal/min, you will exceed the 1000 Hz
full-scale limit:
The best choice for this parameter depends upon the required
resolution, the number of digits in the totalizer, the extent of range
required, and the maximum counter input frequency.
NOTE
For totalizing on the LOI, seven digits are available.
HART Fast Keys 1, 4, 3, 2, 1
LOI Key Aux. Function
1000 gal/min
60 sec/min 0.01 gal/pulse×
--------------------------------------------------------------------------- 1666.65 Hz=
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