Table of Contents
Reference Manual
00809-0100-4728, Rev MB
5. Restore the loop to full operation. Remove the bypass from the safety PLC or otherwise restore
normal operation.
6. Document the test results per the plant's requirements.
Table 7-1. Proof Test Intervals
4-wire RTD
Thermocouple
Dual Thermocouple
Dual 3-wire RTD
Thermocouple and 3-wire RTD
Proof test intervals are based on sensor failure rates from the "Electrical and Mechanical Component
Reliability Handbook, Second Edition", exida, 2008. A low stress environment is assumed, with 30 percent
of SIL 2 PFDavg limit budgeted for the transmitter and sensor element. See the FMEDA report for
additional details or references.
Visual inspection
Not required
Special tools
Not required
Product repair
The Rosemount 644 is repairable by replacement only.
All failures detected by the transmitter diagnostics or by the proof-test must be reported. Feedback can
be submitted electronically at www.EmersonProcess.com/Rosemount/Safety/Safety-Cert-Temp.htm
(Contact Us button).
7.8
Specifications
The Rosemount 644 must be operated in accordance to the functional and performance specifications
provided in the Rosemount 3051 Product Data Sheet (document number 00813-0100-4728).
7.8.1
Failure rate data
The FMEDA report includes failure rates and common cause Beta factor estimates.
The report is available at www.EmersonProcess.com/Rosemount/Safety-Products.
7.8.2
Failure values
Safety accuracy: ±2.0 percent
Transmitter response time: 1.5 second
Self-diagnostics Test: At least once every 60 minutes
Safety Instrumented Systems (SIS) Certification
Sensors
Safety Instrumented Systems (SIS) Certification
Abbreviated proof test
10 years
1 year
2 years
10 years
10 years
10 years
July 2016
Extended proof test
10 years
10 years
2 years
10 years
10 years
10 years
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