42
Reference Manual
00809-0200-4728, Rev SA
Installation
July 2018
Installation
3.2 Safety messages
Instructions and procedures in this section may require special precautions to ensure the safety of the
personnel performing the operations. Information that potentially raises safety issues is indicated by a
warning symbol ( ). Refer to the following safety messages before performing an operation preceded
by this symbol.
3.3 Considerations
3.3.1 General
Electrical temperature sensors such as RTDs and thermocouples produce low-level signals proportional
to their sensed temperature. The Rosemount 644 Transmitter converts the low-level sensor signal to a
standard 4–20 mA DC or digital HART signal that is relatively insensitive to lead length and electrical
noise. This signal is then transmitted to the control room via two wires.
3.3.2 Commissioning
The transmitter can be commissioned before or after installation. It may be useful to commission it on
the bench, before installation, to ensure proper operation and to become familiar with its functionality.
Make sure the instruments in the loop are installed in accordance with intrinsically safe, or non-incendive
field wiring practices.
3.3.3 Installation
Measurement accuracy depends upon proper installation of the transmitter. Mount the transmitter close
to the process and use minimum wiring to achieve best accuracy. Keep in mind the need for easy access,
personnel safety, practical field calibration, and a suitable transmitter environment. Install the
transmitter to minimize vibration, shock, and temperature fluctuation.
Failure to follow these installation guidelines could result in death or serious injury.
Make sure only qualified personnel perform the installation.
Explosions could result in death or serious injury.
Do not remove the connection head cover in explosive atmospheres when the circuit is live.
Before connecting a Field Communicator in an explosive atmosphere, make sure the instruments in
the loop are installed in accordance with intrinsically safe or non-incendive field wiring practices.
Verify the operating atmosphere of the transmitter is consistent with the appropriate hazardous
locations certifications.
All connection head covers must be fully engaged to meet explosion-proof requirements.
Process leaks could result in death or serious injury.
Do not remove the thermowell while in operation.
Install and tighten thermowells and sensors before applying pressure.
Electrical shock could cause death or serious injury.
Use extreme caution when making contact with the leads and terminals.
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