Page 14
ES2 Electronic Liquid Level Transmitter
EX-1845
Calculating Milliamp Output
When Output will be Less Than 20 mA . . .
■
Maximum Pressure Below 3.00 PSI
When the nominal 5 PSI transmitter is used on an applica-
tion whose maximum pressure is less than 3.00 PSI, the
full calculated range output will be less than 20 mA. To
determine the actual milliamp output of the transmitter
when the maximum applied pressure is below the lower
span limit, use the following formula:
(16 × Calculated PSI)
+ 4 = mA Output
3.0
The KING-GAGE ES2 transmitter is factory-calibrated to
nominal range only. Unless span is adjusted for a specific
calculated pressure range, the milliamp output of the sen-
sor at full tank level will generally be less than 20.00 mA.
Actual output can be calculated based on total tank depth
and specific gravity of the liquid product:
(
B
-
A
) ×
C
= Tank Pressure
27.6807
where . . .
A
= Reserve (inches of depth from low point of tank to
sensor)
B
= Full Tank (inches of depth from low point of tank to
full)
C
= Specific Gravity of Tank Contents
MODEL/RANGE
5701-1-15 PSIG
Sensor
Assembly
B
A
Tank
Milk
1.032 sp. gr.
Now, using the calculated tank pressure from above, the
actual milliamp value at full can be determined:
(16 × Tank Pressure) + 4 = mA Output
NOMINAL psig RANGE
(NOTE: If the span setting is turned down from the
nominal range, refer to the calculation for determining
milliamp output.)
Example - mA Output Calculation for Tank Gauging
Application
The following example shows how the milliamp output of
the sensor at full tank can be calculated. The “Reserve”
represents the distance from the lowest point on the bot-
tom of the tank to the installed sensor. “Full” is the level of
contents at which the tank is filled to capacity. The liquid
contents of the tank is milk @ 1.032 sp.gr. The sensor
installed is a nominal 15 psig range model.
C
= 1.032 (specific gravity)
B
= 400 in. (full level)
A
= 28 in. (reserve)
(400 - 28) × 1.032 = 13.87 psig
27.6807
(16 × 13.87) + 4 = 18.79 mA
15 psig
