Dynasonics TFXP Series Transit Time Ultrasonic Flow Meter - Manual (Page 64)

Rev. 5/09
-3.26- TFXP
4-20 mA Span
External Power Configuration (Current Sink): If the 4-20 mA
output module was ordered from the factory for external power
the 4-20 mA module requires power from an external DC power
supply. The voltage of the external power source must be
sufficient to power the module and drive the loop load. The loop
loss attributed to the ISO-MOD is 7 VDC, so the minimum
voltage required to power a loop can be calculated using the
following formula:
Loop Voltage (minimum) = (loop load Ohms × 0.02) + 7
The FL 4MA and FL 20MA entries are used to set the span of the
4-20 mA analog output. These entries are volumetric rate units that
are equal to the volumetric units configured as Engineering Rate
Units and Engineering Units Rate Interval discussed on pages 3.13
and 3.14.
Figure 3.9 — Loop Load Chart
PART 3 - KEYPAD CONFIGURATION