Reference Manual
00809-0600-4026, Rev BA
December 2011
Rosemount Process Radar
5-16
Safety Instrumented
Systems (4-20 mA only)
The following section applies to the 4-20 mA Rosemount 5400 Series with QS
Prior-Use Certificate of FMEDA data transmitter used in Safety Instrumented
Systems (SIS). Additional Safety Instrumented Systems information is
available in the Rosemount 5400 Series Reference Manual supplement
(Document No. 00809-0400-4026). The manual is available electronically at
www.rosemount.com or by contacting an Emerson Process Management
representative.
To identify a 5400 QS Prior Use transmitter, verify the option code QS in the
model code, on the label affixed to the outside of the transmitter head.
NOTE
The Rosemount 5400 Series transmitter is not safety-rated during
maintenance work, configuration changes, multidrop, loop test, or other
activity that affects the Safety Function. Alternative means should be used to
ensure process safety during such activities.
Installation
The device should be installed and configured as a level sensing device per
manufacturer’s instructions. The materials must be compatible with process
conditions and process fluids. No special installation is required in addition to
what is described in this document.
Environmental limits are available in the Rosemount 5400 Series Reference
Manual (Document No. 00809-0100-4026), Appendix A: Reference Data.
NOTE
False echoes within the radar beam from obstructions may lead to a situation
where the Rosemount 5400 Series can no longer be used for safety related
functions with the listed failure rates, Safe Failure Fraction, and PFD
AVG
.
However, reduced proof test intervals can help to detect such unwanted
causes.
The loop must be designed so the terminal voltage does not drop below the
minimum input voltage, see values in Table 5-2, when the transmitter output is
21.75 mA. The input voltage U
i
for HART is 16-42.4 Vdc (16-30 Vdc in IS
applications, and 20-42.4 Vdc in Explosion-proof/Flameproof applications).
The HART loop must be referenced to ground in one point, located between
the power supply and the load resistor. Either the negative or the positive pole
of the power supply can be ground referenced, depending on the placement
of the load resistor. See Figure 5-1 as an example.
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