Quick Installation Guide
00825-0300-4728, Rev AA
July 2010
Rosemount 644
5
S
TEP
2: W
IRE
AND
A
PPLY
P
OWER
• Wiring diagrams are located inside the terminal block cover and on the transmitter top
label.
• An external power supply is required to power a Profibus segment.
• The power required across the transmitter power terminals is 9 to 32 VDC (the power
terminals are rated to 32 VDC). To prevent damaging the transmitter, do not allow
terminal voltage to drop below 9 VDC when changing the configuration parameters.
Power Filter
A Profibus segment requires a power conditioner to isolate the power supply filter and
decouple the segment from other segments attached to the same power supply.
Power the Transmitter
1. Remove the terminal block cover (if applicable).
2. Connect the power lead to the power terminals (The 644 power terminals are polarity
insensitive for the Profibus protocol.)
3. Tighten the terminal screws. When tightening the sensor and power wires, the max
torque is 6 in.-lbs. (0.7 N-m).
4. Reattach and tighten the cover (if applicable).
5. Apply power (9 – 32 VDC).
Sensor Connections Diagram
* The transmitters must be configured for at least 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 3-wire configurations by leaving the unneeded leads disconnected and insulated with electrical
tape.
1 2 3 4
Sensor Terminals
Communication Terminals
Power Terminals
2-wire
RTD and
⍀
3-wire RTD
and
⍀
4-wire RTD
and
⍀
T/C
and mV
**
*
1 2 3 4
1 2 3 4
1 2 3 4
1 2 3 4
4728_Rev AA.fm Page 5 Thursday, July 29, 2010 11:41 AM
