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F-1500 Turbine Flow Meter Manual 02/18 - 1018-6 / 35726
Page 28
2.6.4 Pulse Output Connections
The pulse output is used for a remote counter. When the preset volume or mass (defined
in the totalizer settings, on page 62) has passed the meter, the output provides a 50
millisecond square pulse.
The pulse output optical relay is a normally-open single-pole relay. The relay has a
nominal 200 V / 160 ohm rating. This means that it has a nominal on-resistance of 160
ohms, and the largest voltage that it can withstand across the output terminals is 200 V.
However, there are current and power specifications that must be observed. The relay
can conduct a current up to 40 mA and can dissipate up to 320 mW. The relay output is
isolated from the meter electronics and power supply.
There are three connection options for the pulse output. The first has a separate power
supply (Figure 37). The second uses the flow meter power supply (Figure 38) (DC powered
units only), and the third uses the internal 24 VDC power supply (Figure 39)(AC powered
units only). Use the first option with a separate power supply (5 to 36 VDC) if a specific
voltage is needed for the pulse output. Use the second configuration if the voltage at the
flow meter power supply is an acceptable driver voltage for the load connected. (Take into
account that the current used by the pulse load comes from the meter’s power supply).
Use the third configuration if you have an AC powered unit only. In any case, the voltage
of the pulse output is the same as the voltage supplied to the circuit.
AC or DC powered meters
PWR
PWR
DC Powered meters only
+
24 VDC Out
- 24 VDC Out
AC units only
Meter provided DC Power
Figure 27. Isolated Pulse Output Using External Power Supply
F
igure 28. Non-Isolated Pulse Output Using Input Power Supply
Figure 29. Isolated Pulse Output Using Meter Provided Power Supply
Pulse voltage = +V
Select resistor so that current
through pulse ≤ 40 mA.
DC powered meters only
AC units only
Meter provided DC power