P
RO
V
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™ PD6088/PD6089 Modbus
®
Scanner
Instruction Manual
53
Programmable Exponent Function Menu (
prog e
)
The programmable exponent function is used to calculate open-channel flow measured with a level transmitter in
weirs and flumes. The flow rate is proportional to the head height. Scale the scanner so that the low input signal (e.g.
4 mA) is equal to zero flow and the high input signal (e.g. 20 mA) is equal to the maximum flow. This method works
well for all weirs and flumes that have a simple exponent in the flow calculation formula. For weirs and flumes with
complex exponents it is necessary to use a strapping table and the 32-point linearization of the scanner.
Round Horizontal Tank Function
Menu (
rht
)
This function is used to calculate volume in a round
horizontal tank with flat ends. The volume is
calculated based on the diameter and length of the
tank. The tank’s dimensions can be entered in inches
or centimeters; the scanner automatically calculates
the volume in gallons or liters. After entering the
dimensions, complete the scaling process with the
display values calculated by the scanner. The
scanner can be re-scaled to display the volume in any
engineering unit without the need to re-enter the
dimensions again.
Changing the Volume from Gallons to Liters
In the graphic, entering the 48" for the diameter and
120" for the length of the round horizontal tank, the
scanner automatically calculates that the volume of
the tank is 940.02 gallons.
1. Convert gallons to liters
1 US gallon = 3.7854 L
940.02 gal = 3558.4 L
2. Go to the
Setup - PV - Decimal Point
menu and
change the decimal point to 1 decimal.
3. Go to the
Setup
-
PV
-
Scale
menu and press
Enter until
dis 2
is shown on display line 1.
4. Press Enter and change the display 2 value to
3558.4.
5. The scanner is now displaying the volume in liters.
Note: The display can be scaled to display the volume
in any engineering units.
SAVED flashes
before moving
to next PV.
