24
Reference Manual
00809-0100-4021, Rev GC
Section 2: Installation
April 2014
RTD or ohm inputs
If the transmitter is mounted remotely from a 3- or 4-wire RTD, it will operate within specifica-
tions, without recalibration, for lead wire resistances of up to 60 ohms per lead (equivalent to
1,000 feet of 20 AWG wire). In this case, the leads between the RTD and transmitter should be
shielded. If using only two leads (or a compensation loop lead wire configuration), both RTD
leads are in series with the sensor element, so significant errors can occur if the lead lengths
exceed one foot of 20 AWG wire. For longer runs, attach a third or fourth lead as described
above. To eliminate 2-wire lead resistance error, the 2-wire offset command can be used. This
allows the user to input the measured lead wire resistance, resulting in the transmitter adjusting
the temperature to correct the error.
Thermocouple or millivolt inputs
For direct-mount applications, connect the thermocouple directly to the transmitter. If
mounting the transmitter remotely from the sensor, use appropriate thermocouple extension
wire. Make connections for millivolt inputs with copper wire. Use shielding for long runs of wire.
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.
2.6
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
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.
Summary of Contents for Rosemount
Page 1: ...Reference Manual 00809 0100 4021 Rev GC April 2014 Rosemount 3144P Temperature Transmitter ...
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Page 4: ...iv Reference Manual 00809 0100 4021 Rev GC Title Page April 2014 ...
Page 10: ...x Reference Manual 00809 0100 4021 Rev GC Table of Contents April 2014 Table of Contents ...
Page 38: ...28 Reference Manual 00809 0100 4021 Rev GC Section 2 Installation April 2014 Installation ...
Page 188: ...178 Reference Manual 00809 0100 4021 Rev GC Section 5 Maintenance April 2014 Maintenance ...
Page 250: ...Index 244 Reference Manual 00809 0100 4021 Rev GC Index April 2014 Index ...
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