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F-2600 & F-2700 Vortex Flow Meter Manual 02/15 - 0808-7 / 19204 Page 36

2.6.2 4-20 mA OUTPUT CONNECTIONS

The loop powered meter has a single 4-20 mA loop. The 4-20 mA loop current is

controlled by the meter electronics. The electronics must be wired in series with the sense

resistor or current meter. The current control electronics requires at least 12 volts at the

input terminals to operate correctly.

The maximum loop resistance (load) for the current loop output is dependent upon the

supply voltage and is given in Figure 18. The 4-20 mA loop is optically isolated from the

ow meter electronics.

load

is the total resistance in the loop, including the wiring resistance (R

load

= R

wire

+ R

sense

To calculate R

max

, the maximum Rl

oad

for the loop, subtract the minimum terminal voltage

from the supply voltage and divide by the maximum loop current, 20 mA. Thus:

The maximum resistance R

load

= R

max

= (V

supply

– 12V) / 0.020 A

Figure 18. Load Resistance Versus Input Voltage

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Onicon F-2600 Manuale Utente Pagina 36