Alarm overload is an issue most control rooms must deal with on an ongoing basis and relieving the situation is a priority for most process engineering professionals. Much of the burden has been caused by DCS and scada systems delivering too much information to operators who are then under pressure to make decisions and take corrective action.
While it is not disputed that all this information is important to a smooth-running process, it is important to differentiate between the types of information collected by the supervisory systems and to classify alarms requiring action from status information. The role of the alarm system is to prompt operator intervention to act and return the process to optimum levels or to safe conditions.
Critical alarms are often managed with the use of annunciators as a separate layer of plant protection over and above the supervisory system. However, even this methodology does not always reduce the load on operators who are trying to service alarms coming into the control room. Standards like ISA 18.1 and EEMUA 191 Alarm Systems are extremely valuable in rationalising the alarm management process, but they are generic and every plant or process has its own unique issues when it comes to abnormal conditions. Many schools of thought have sought to relieve the pressure on operators in those cases and they often boil down to differentiating the types of alarm using audio visual stimuli.
An option to rationalise the alarm system into voice alarms broadcast over the PA system, allows busy operators to hear and evaluate the urgency without leaving what they are currently doing. Alarms are voice recorded into WAV files and embedded on the HMI ready to be triggered by the Alarm Marshalling unit which is monitoring the existing alarm systems, which could be a PLC or scada, as well as existing Omni16 Annunciator systems. An alarm banner on the HMI provides further information on the alarm. Unresolved alarms will also flash after a period of time to remind operators of their status and importance. The system provides real benefits to operator efficiency including:
• Customisation of existing alarm systems.
• Reduced operator stress from multiple alarm sources.
• Operators can discriminate the status of alarms timeously.
• Critical alarms to have an additional level of differentiation.
For more information contact Ian Loudon, Omniflex Remote Monitoring Specialists, +27 31 207 7466, sales@omniflex.com, www.omniflex.com
Tel: | +27 31 207 7466 |
Fax: | +27 31 208 2058 |
Email: | sales@omniflex.com |
www: | www.omniflex.com |
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