Reference Manual
00809-0100-4021, Rev FB
August 2011
2-13
Rosemount 3144P
Sensor Connections
The correct sensor wiring connections to the transmitter sensor terminals are
shown in and Figure 2-8 on page 2-11 (HART) Figure 2-13 on page 2-14
(F
OUNDATION
fieldbus). To ensure an adequate sensor connection, anchor the
sensor lead wires beneath the flat washer on the terminal screw. Do not
remove the transmitter cover in explosive atmospheres if the circuit is live.
Both transmitter covers must be fully engaged to meet explosion-proof
requirements. Use extreme caution when making contact with the leads and
terminals.
RTD or Ohm Inputs
If the transmitter is mounted remotely from a 3- or 4-wire RTD, it will operate
within specifications, without recalibration, for lead wire resistances of up to
10 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.
Figure 2-12. Sensor Wiring Diagram for F
OUNDATION
fieldbus
3144P Single-Sensor Connections Diagram
3144P Dual-Sensor Connections Diagram
*
Transmitter must be configured for a 3-wire RTD in order to recognize an RTD with a compensation loop.
** Emerson Process Management provides 4-wire sensors for all single-element RTDs. Use these RTDs in 2-wire or 3-wire configurations by
leaving the unneeded leads disconnected and insulated with electrical tape.
4-wire RTD
and Ohms
T/Cs and
Millivolts
RTD with
Compensation Loop*
2-wire RTD
and Ohms
3-wire RTD
and Ohms**
T/Hot
Backup/Dual
Sensor with 2
RTDs
T/Hot Backup/Dual
Sensor with 2
Thermocouples
T/Hot
Backup/Dual
Sensor with RTDs/
Thermocouples
T/Hot
Backup/Dual
Sensor with RTDs/
Thermocouples
T/Hot Backup/Dual
Sensor with 2 RTDs
with Compensation
Loop
**
**
**
Aotewell Ltd
www.aotewell.com
Industry Automation
HongKong|UK|China
+86-755-8660-6182
