Azbil PTG71, User Manual

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Wiring Azbil Corporation
3-4 Model PTG71 / 72 - Smart Pressure Transmitter
Power supply and external load resistance
External load resistance should be determined in relation to the voltage of the power
supply so that both fall inside the diagonally-shaded area below.
External load resistance is the total resistance connected to the output terminals of the
Transmitter, which includes the resistance in the cables forming the loop, the internal
resistance in instruments connected between the Transmitter and the power supply,
etc.
The abscissa axis shown in the figure is the voltage of the Transmitter’s power supply
and the ordinate axis is the external load resistance.
11.5 16.9 30
0
Operating
range
A load resistance of
250
Ω
is required for
communicator.
250
( )
External load resistance (
Ω
)
Supply voltage (V DC)
850
Figure 3-2 Relationship between power supply voltage and external load
resistance