One of the necessities in managing safety instrumented systems throughout the IEC 61511 safety lifecycle is to perform periodic proof tests on the components in a safety instrumented function to verify proper function.
A short 2:44 YouTube video, How to Remotely Proof-Test the Rosemount 2140:SIS shows how this proof testing can be performed remotely for safety level switches to save time & costs and reduce risk.
The video highlights the traditional approach to proof test level devices by climbing up tanks, possibly shutting down the process, and removing the devices to conduct the tests. The Rosemount 2140:SIS Point Level Detector is a vibrating fork switch that simplifies the proof testing.
This level switch has a fully integrated partial proof test function where functional tests can be initiated remotely through a HART-based command by operators in the control room. No additional wiring or space is required unlike traditional solutions with external switching units and cabinet terminations.
Once initiated, the device enters test mode and cycles through different current output levels to exercise the processing and output electronics. This helps to identify dangerous undetected failures which prevent the device from performing correctly on demand. This test takes only minutes to complete before returning to operational mode. These partial proof tests help to extend the time interval before full proof tests are required.
Learn more about vibrating fork and other point level detection technologies in the Point Level Detection section on Emerson.com. You can also connect and interact with other level measurement and safety instrumentation experts in the Measurement Instrumentation group in the Emerson Exchange 365 community.