Emerson Rosemount 644, Reference Manual

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54
Reference Manual
00809-0200-4728, Rev RA
Section 3: Hardware installation
April 2015
Hardware Installation
Rail mount transmitter with threaded sensor
1. Attach the transmitter to a suitable rail or panel.
2. Attach the thermowell to the pipe or process container wall. Install and tighten the
thermowell before applying pressure.
3. Attach necessary extension nipples and adapters. Seal the nipple and adapter threads
with thread sealant.
4. Screw the sensor into the thermowell. Install drain seals if required for severe
environments or to satisfy code requirements.
5. Screw the connection head to the sensor.
6. Attach the sensor lead wires to the connection head terminals.
7. Attach additional sensor lead wires from the connection head to the transmitter.
8. Attach and tighten the connection head cover. Enclosure covers must be fully engaged
to meet explosion-proof requirements.
9. Set the transmitter failure mode switch.
10. Attach the sensor wires to the transmitter.o
3.4.4 Multichannel installations
In a HART installation, several transmitters can be connected to a single master power supply, as
shown in
Figure 3-5 . In this case, the system may be grounded only at the negative power
supply terminal. In multichannel installations where several transmitters depend on one power
supply and the loss of all transmitters would cause operational problems, consider an
uninterrupted power supply or a back-up battery. The diodes shown in
Figure 3-5 prevent
unwanted charging or discharging of the back-up battery.
A. Rail mount transmitter
B. Threaded sensor connection head
C. Standard extension D. Threaded style sensor
E. Threaded thermowell
A
D
E
C
B