Amplitude Threshold; Write Protection; Site Acceptance; Operation And Maintenance - Emerson Rosemount 5402 Reference Manual

Safety Instrumented Systems (4-20 mA Only)
October 2018
8.5.3

Amplitude threshold

For amplitude thresholds, verify that:
the Amplitude Threshold is at least 50% greater than the amplitude of disturbances.

For example, if the amplitude of disturbance is 1000 mV, the Amplitude Threshold should be at least
1500 mV.
the Amplitude Threshold has an amplitude of at least 100 mV

the Amplitude Threshold is set to 20-50% of the signal amplitude of the product surface

Amplitude Thresholds should be verified with the measured product in the tank. It is not recommended
to register any false echo areas. For more information on Amplitude Thresholds, see
page
8.5.4

Write protection

A Rosemount 5400 can be protected from unintentional configuration changes by a password protected
function. It is recommended to use write protection described in
page
8.5.5

Site acceptance

After the installation and configuration, proper operation of the transmitter should be verified. A site
acceptance test is therefore recommended. The proof test outlined in this section can be used for this.
Note that re-verification of the transmitter operation is recommended if the configuration is changed.
8.6

Operation and maintenance

8.6.1

General

The Rosemount 5400 QS option must be tested at regular intervals to confirm that the overfill and
empty tank protection function result in the desired system response. The required proof test intervals
are dependent on the configuration of the transmitter and the process environment. It is the
responsibility of the operator/owner of the system to determine the sufficient time interval and verify it
is followed. For more information, see Rosemount.com/safety.
If the overfill and empty tank protection function cannot be tested by a controlled filling to the response
height, suitable simulation of the level must be used to make the level sensor respond.
The following proof test is recommended. If an error is found in the safety functionality, the measuring
system must be switched out of service and the process held in a safe state by means of other measures.
Proof test results and corrective actions taken must be documented at Rosemount.com/safety.
Proof test
This test detects approximately 95% of the possible Dangerous Undetected (DU) failures of the
transmitter. Instructions for performing the proof test with the Field Communicator, Rosemount Radar
Master, or AMS Suite, are available in
the test, the echo curve should be inspected to ensure that no disturbing echoes affecting the
measurement performance are present in the tank.
Required Tools: HART host/communicator and mA meter.
202
109, "ATC" on page 110, and
180.
"Analyzing the measurement signal" on page
Appendix D: Performing Proof
Reference Manual
00809-0100-4026, Rev KC
"Echo tuning" on
162.
"Write protecting a transmitter" on
Test. Note that prior to conducting
Safety Instrumented Systems (4-20 mA Only)