Table of Contents
Safety Instrumented Systems (SIS) Certification
July 2016
7.7
Rosemount 644 SIS operation and maintenance
7.7.1
Proof test
The following proof tests are recommended. In the event that an error is found in the safety
functionality, proof test results and corrective actions taken must be documented at www.EmersonPro-
cess.com/Rosemount/Safety. Use
and view status.
The required proof test intervals depends upon the transmitter configuration and the temperature
sensor(s) in use. Guidance is available in
for further information.
7.7.2
Abbreviated proof test
Conducting the abbreviated proof test detects approximately 63 percent of transmitter DU failures, and
approximately 90 percent of temperature sensor(s) DU failures, not detected by the Rosemount 644
safety-certified automatic diagnostics, for a typical overall assembly coverage of 67 percent.
1. Bypass the safety PLC or take other appropriate action to avoid a false trip.
2. Using Loop Test, enter the milliampere value representing a high alarm state.
3. Check the reference meter to verify the mA output corresponds to the entered value. This tests for
compliance voltage problems such as a low loop power supply voltage or increased wiring resistance.
This also tests for other possible failures.
4. Using Loop Test, enter the milliampere value representing a low alarm state. This tests for possible
dormant current related failures.
5. Check the reference meter to verify the mA output corresponds to the entered value.
6. Use a Field Communicator to view detailed device status to ensure no alarms or warnings are present
in the transmitter.
7. Check that sensor value(s) are reasonable in comparison to a basic process control system (BPCS)
value.
8. Restore the loop to full operation. Remove the bypass from the safety PLC or otherwise restore
normal operation.
9. Document the test results per the plant's requirements.
7.7.3
Extended proof test
Conducting the extended proof test, which includes the abbreviated proof test, detects approximately
96 percent of transmitter DU failures and approximately 99 percent of temperature sensor(s) DU failures,
not detected by the Rosemount 644 safety-certified automatic diagnostics, for a typical overall assembly
coverage of 96 percent.
1. Bypass the safety PLC or take other appropriate action to avoid a false trip.
2. Execute the abbreviated proof test.
3. Perform a minimum two point sensor verification check. If two sensors are used, repeat for each
sensor. If calibration is required for the installation, it may be done in conjunction with this
verification.
4. Verify the housing temperature value is reasonable.
80
Table C-1 on page 155
to perform looptest, review device variables,
Table 7-1 on page
81. Refer to the Rosemount 644 FMEDA report
Reference Manual
00809-0100-4728, Rev MB
Safety Instrumented Systems (SIS) Certification
Table of Contents
