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Reference Manual
00809-0100-4021, Rev FB
August 2011
Rosemount 3144P
2-14
NOTE
For HART transmitters, the use of two grounded thermocouples with a dual
option 3144P transmitter is not recommended. For applications in which the
use of two thermocouples is desired, connect either two ungrounded
thermocouples, one grounded and one ungrounded thermocouple, or one
dual element thermocouple.
POWER SUPPLY
HART
An external power supply is required to operate the 3144P (not included). The
input voltage range of the transmitter is 12 to 42.4 Vdc. This is the power
required across the transmitter power terminals. The power terminals are
rated to 42.4 Vdc. With 250 ohms of resistance in the loop, the transmitter
requires a minimum of 18.1 Vdc for communication.
The power supplied to the transmitter is determined by the total loop
resistance and should not drop below the lift-off voltage. The lift-off voltage is
the minimum supply voltage required for any given total loop resistance. See
Figure 2-13 to determine the required supply voltage. If the power drops
below the lift-off voltage while the transmitter is being configured, the
transmitter may output incorrect information.
The dc power supply should provide power with less than 2% ripple. The total
resistance load is the sum of the resistance of the signal leads and the load
resistance of any controller, indicator, or related piece of equipment in the
loop. Note that the resistance of intrinsic safety barriers, if used, must be
included.
NOTE
Permanent damage to the transmitter could result if the voltage drops below
12.0 Vdc at the power terminals, when changing transmitter configuration
parameters.
Figure 2-13. Load Limits.
F
OUNDATION
fieldbus
Powered over F
OUNDATION
fieldbus with standard fieldbus power supplies, the
transmitter operates between 9.0 and 32.0 Vdc, 11 mA maximum. Transmitter
power terminals are rated to 42.4 Vdc.
The power terminals on the 3144P with F
OUNDATION
fieldbus are polarity
insensitive.
Maximum Load = 40.8 X (Supply Voltage - 12.0)
1240
1000
750
250
0
10
12.0
20
30
40 42.4
Supply Voltage (Vdc)
Operating
Region
4–20 mA dc
Loa
d (O
h
m
s)
500
1100
Aotewell Ltd
www.aotewell.com
Industry Automation
HongKong|UK|China
+86-755-8660-6182