Wiring And Powering The Transmitter - Emerson Rosemount 644 Reference Manual

Electrical Installation
March 2021
WARNING
Physical access
Unauthorized personnel may potentially cause significant damage to and/or
misconfiguration of end users' equipment. This could be intentional or unintentional and
needs to be protected against.
Physical security is an important part of any security program and fundamental to
protecting your system. Restrict physical access by unauthorized personnel to protect end
users' assets. This is true for all systems used within the facility.
4.3

Wiring and powering the transmitter

All power to the transmitter is supplied over the signal wiring. Use ordinary copper wire of
sufficient size to ensure the voltage across the transmitter power terminals does not drop
below 12.0 Vdc.
If the sensor is installed in a high-voltage environment and a fault condition or installation
error occurs, the sensor leads and transmitter terminals could carry lethal voltages. Use
extreme caution when making contact with the leads and terminals.
Note
Do not apply high voltage (e.g., ac line voltage) to the transmitter terminals. Abnormally
high voltage can damage the unit. (Sensor and transmitter power terminals are rated to
42.4 Vdc. A constant 42.4 volts across the sensor terminals may damage the unit.)
For multichannel HART installations, the transmitters will accept inputs from a variety of
RTD and thermocouple types. Refer to
The sensor wiring diagram is located on the device's top label below the terminal screws.
See Figure 4-1
types to the transmitter.
Figure 4-1: Wiring Diagram Location
74
and Sensor wiring for where to find and how to correctly wire all sensor
Head mount transmitter
Figure 2-7 when making sensor connections.
Field mount transmitter
Reference Manual
00809-0200-4728
Emerson.com/Rosemount