Safety instrumented systems (SIS) operated in ‘low demand mode’ require a regular functional check. The safety characteristics of the components (sensor, logic and final control element) determine the interval.
To verify its function in such an application, the sensor usually has to be dismounted or brought in contact with the measured medium – a procedure that in most cases cannot be accomplished while production is in progress. Moreover, this kind of test is usually very cost-intensive, and filling a vessel up to the overfill protection trigger point to verify sensor functionality also carries risks.
A function test on Vega’s vibrating level switches Vegaswing, Vegavib and Vegawave can be done via keystroke from the Vegator 636 signal conditioning instrument, or shortly interrupting the signal line. The scope of this test, which can be carried out in the middle of a running process, fulfils the requirements of both WHG (Water Resource Act) and SIL (Safety Integrity Level) as a periodic check.
What about continuously measuring sensors?
Previously, continuous level transmitters could not be checked extensively without influencing the ongoing process and without a reference measurement. There is now a testing method available for Vega’s guided microwave and radar sensors to allow a ‘recurring function test’ to be performed without influencing the ongoing process. The operator of a plant can thus reduce the work and costs that are otherwise involved in such checks – eg, dismounting the sensor or bringing the sensor and the measured product into contact – and so avoid the production stoppages resulting from these checks.
The function check reduces test overheads considerably and consists of:
* A restart of the sensor.
* The simulation of 4 and 20 mA current.
* A check of the parameter settings and echo data.
Precision in paper processing VEGA Controls SA
Editor's Choice Level Measurement & Control
Paper manufacturing is a demanding process that relies on consistency, precision and control at every stage. The VEGABAR 82 pressure transmitter is well-suited to these harsh environments.
Read more...VEGA’s Lunch-and-Learn success in KZN VEGA Controls SA
News
VEGA has rolled out its new Lunch-and-Learn series to the coastal regions of South Africa, designed to bring practical training and real-world insights directly to engineers and technicians.
Read more...Where every grain counts VEGA Controls SA
Level Measurement & Control
VEGA’s advanced level and pressure measurement solutions offer transformative technologies to improve grain storage management in sub-Saharan Africa.
Read more...Paper might carry the message, but pressure carries the process VEGA Controls SA
Pressure Measurement & Control
VEGABAR pressure transmitters are designed to address the unique challenges faced by the pulp and paper industry. Built for durability and precision, they ensure reliable pressure monitoring in aggressive environments.
Read more...Capsules, steam and cream VEGA Controls SA
Pressure Measurement & Control
African cosmetic brands are increasingly outsourcing production to specialised contract manufacturers who use automation and high-precision tools to ensure quality and adapt quickly to regulatory changes. VEGA’s suite of level and pressure measurement solutions offers a robust foundation for profitability and quality assurance.
Read more...Differential pressure measurement made simple VEGA Controls SA
Pressure Measurement & Control
The VEGADIF 85 serves as an exemplary model of a differential pressure sensor. It combines universal applicability with high operational dependability and integrated overload protection, ensuring consistent performance even in the harshest conditions.
Read more...Small, inexpensive radar level transmitters VEGA Controls SA
Level Measurement & Control
Anyone who needs to keep processes running needs level measurement technology that measures reliably. However, what is needed is not always the most ‘fully featured’ solution, but the smartest one. This is exactly what VEGAPULS radar transmitters of the BASIC series do.
Read more...Meeting the challenges of tank obstructions interfering with radar
Level Measurement & Control
One of the most challenging applications for non-contacting radar level transmitters is measuring level in tanks with internal obstructions, such as agitators, heating coils, pipes, ladders or baffles. Rosemount non-contacting radar level transmitters from Emerson feature an advanced solution that enables accurate and reliable level measurements in tanks with obstructions.
Read more...A fresh approach to dairy processing VEGA Controls SA
Level Measurement & Control
Ensuring the quality and safety of milk throughout the production process is of the utmost importance in the dairy industry. The VEGABAR pressure transmitters are suitable for hygienic applications. They are an asset in the dairy industry and have been used with success for measuring the milk level and the process pressure in storage tanks.
While every effort has been made to ensure the accuracy of the information contained herein, the publisher and its agents cannot be held responsible for any errors contained, or any loss incurred as a result. Articles published do not necessarily reflect the views of the publishers. The editor reserves the right to alter or cut copy. Articles submitted are deemed to have been cleared for publication. Advertisements and company contact details are published as provided by the advertiser. Technews Publishing (Pty) Ltd cannot be held responsible for the accuracy or veracity of supplied material.
printer friendly version