Panametrics PanaFlow MV80, Руководство пользователя, Страница: 53 / 184

+ Pwr
– Pwr
DC Power
18 to 36 VDC @300 mA Max.
DC Common
PanaFlow™ MV80, MV82 & MV84 User’s Manual 41
Chapter 2. Installation
Figure 34: DC Power Connections
2.6.2 4-20 mA Output Connections
The standard PanaFlow meter has a single 4-20 mA loop. Two additional loops are available on the optional
communication board. The 4-20 mA loop current is controlled by the meter electronics. The electronics must be
wired in series with the sensor resistor or current meter (see
Figure 35 , Figure 36 or Figure 37 below). The current
control electronics requires 12 volts at the input terminals to operate correctly.
4-20 mA +
4-20 mA –
4-20 mA voltage = +V
mA
+V
Meter
R > 250
–
L
–V
For Hart Communications
signal loop must have a
minimum of 250 ohms load
resistance R .
L
For AC and DC
powered meters
Figure 35: Isolated 4-20 mA Output with External Power Supply
+ Pwr
– Pwr
DC Power 4-20 mA +
4-20 mA – DC Common
only
mA Meter
For HART
communications,
the signal loop must
have a minimum of
250 ohms load
resistance.
R > 250 Ohm
L
DC powered meters
Figure 36: Non-Isolated 4-20 mA Output Using Meter Input Power Supply
+ 24 VDC
– 24 VDC
4-20 mA +
4-20 mA –
Meter Provided
mA Meter
For HART
communications,
the signal loop must
have a minimum of
250 ohms load
resistance.
R > 250 Ohm
L
AC units only.
DC Power
Figure 37: Isolated 4-20 mA Output Using Meter Provided Power Supply