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STA 1oo2 Voting with High Availability

STA 1oo2 Voting with High Availability
A customer has a Safety Instrumented Function they need to implement with two independent level transmitters (radar), each wired to a separate STA Functional Safety Trip Alarm. The process will trip if either level reaches the set point, for example a 1 out of 2 (1oo2) voting. However, if the alarm trip (STA) detects an input or unit fault. The customer did not want the process to trip. Instead they wanted to take the faulty unit out of service leaving the process running with the one good level and alarm trip. 
Published: November 28, 2017

Product of the Month: STA Functional Safety Trip Alarm

Product of the Month: STA Functional Safety Trip Alarm
Risk reduction, reliability, and safety are important factors in the automated control of potentially hazardous processes such as the overpressure and containment of dangerous substances. Process Industry personnel are always aware of the need to protect people, the environment, and facilities as part of their overall risk management plan. A central strategy employed today includes safety instrumented functions (SIF), or functional safety, utilizing IEC 61511 standards. A crucial instrument in a safety instrumented system is the logic solver, which acts as a decision maker initiating the final action to make the process safe should the need arise.
Published: January 19, 2017

EHELP: STA Latching Checkbox

EHELP: STA Latching Checkbox

Q: We do not have sufficient PLC digital output spares to perform a Manual Reset of the three installed safety temperature controllers. We are going to remove the alarm latching on both limits and faults on our STA Functional Safety Alarm Trip. The Manual Reset radio button stays active in the STA configuration software. Will the latches clear after we are outside the dead band limits? 

Published: January 10, 2017

Alumina Refinery: Overpressure Protection of a Filter Vessel

Mining & Metal Refining Industry

Alumina Refinery: Overpressure Protection of a Filter Vessel
The process of converting bauxite to alumina for aluminium metal refining involves a complex manufacturing process.  Much of this process requires critical temperature and pressure control, which if left unchecked could result in catastrophic consequences. Learn how Moore Industries solved this problem for an alumina refinery in Australia.
Published: October 20, 2016

EHELP: How do I protect the STA from external voltage surges?

EHELP: How do I protect the STA from external voltage surges?

Q: We want to install an
STA / HLPRG / 3PRG / U / -AO [DIN] into our process and plan to use 4-20mA output loop voltage sourced by a DCS for the analog output, however this voltage may fault at up to 132 VAC. Should we design in fuse protection to the external voltage circuit upstream of the STA to protect it from these surges? Or does the STA include features that protect it from these faults?

Published: June 14, 2016
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