ANNUNCIATORS alarm systems waning?

Commodities with no future? Not quite – systems are still developing with technologies to meet changing user needs by Brian Tinham

Although alarm systems and annunciators have joined the vast majority of equipment in adopting modern electronics and microcomputing technologies – and thus had their functionality/price ratio transformed – this seems now to be a market in decline. At least, so say Gary Napier and Don Harding at Rochester Instrument Systems, self-proclaimed alarm leader in the UK.

Why? Napier: ‘Alarms and alarm-handling are increasingly being integrated into DCS, SCADA and PLC systems. Fire and gas and shutdown systems remain unaffected, but we’re seeing ever more process control systems moving over to screen-based alarm management. Since the take-up of SCADA over the last two or three years, we’ve seen alarm annunciator sales fall 20%.’

And it’s not just the flashing panels of stand-alone alarm modules that have been impacted. Front end conditioning, trip amps, terminations and wiring have all been cut. Duplication of these is fast being consigned to the history books – except where msec resolution is required.

Intelligent systems

Today, most alarm annunciators and systems are being equipped with, for example, Modbus for access to ‘real time’ data already being gathered by the control system. They’re being forced down the line of providing intelligent, easy to install and maintain lamp boxes with universal bi-directional comms.

Is this then the end of alarm annunciators as wall-, or panel-mounting, or remote devices? Is it also the end of distributed alarm systems as such?

No, says Harding: ‘Despite the integration, it’s unlikely that all alarms and alarm management will be handled in this way. At the very least, critical parameters will still be monitored and presented separately. Operators need attention-grabbing immediacy when it matters – and instant critical/non recognition.’

As Alan Pinfold of Panalarm stated in our December 1996 alarms survey: ‘Although most DCS/SCADA packages are equipped with an alarm handling capability, there remains a requirement for a stand-alone annunciator – especially for critical process alarms.’

Napier goes further: ‘While PLCs appear all-powerful, and alarm systems quite simple, fact is they’re designed for the job. You get configurable and programmable sequences, signal duplication and reflash of remote alarms to control centres, inhibited logic on start-up, etc. But you also get flexible alarm acknowledgement, msec time stamp- ing and first-up alarm discrimination – for diagnostics and instant operator decision support. And, you get all this at a price per point which has barely changed since the mid ‘70s!’

And there’s another issue – reliability. Alarms – stand-alone and systems – have perforce always had this as a basic tenet. So it’s quite common to find alarm panels 25 or 30 years old still happily running. The lamps themselves were the only weak link – and they’ve long since been replaced by bright LED technology, with the leaders still looking at further improvements.

Be all this as it may, companies like Rochester, Panalarm, Ronan and Conlog have had to come to terms with a different world. Stand-alone annunciators are now a commodities business, with the technology largely taken for granted. There are still improvements – like Rochester’s AN6100B at the C&I Show, now featuring two-part pluggable terminals for all connections. But the reality is it’s all about price and distribution.

Meanwhile, on the systems side it’s about selling solutions – with engineering largely done by system integrators and contractors; less end users. And here things look slightly better. Both systems and in particular Sequence of Event Recorders (SERs) are seeing more interest, notably offshore and in power distribution (for example in remote substations on local alarm panels).

Recent enhancements here include easier programmability and direct inputs with built-in trip amps. Napier: ‘This feature alone cuts installed costs by about 50% against earlier modular systems.’