Choosing a Signalling Device: The Questions Worth Asking First

Getting a signalling device right is about matching a handful of practical decisions to the conditions the device will face on site.

Auer Signal's white paper offers a framework to make that decision easier. Here's a practical quick guide built around what matters most when specifying for a panel, machine or plant.

Power supply and control

Most of the time, the equipment you're connecting into already sets the voltage you need.

•     24V is the standard control voltage in most machine and control cabinet builds

•     12V suits vehicles and mobile work equipment

•     48V is common for country-specific applications, including here in Australia

•     110V to 240V mains voltages suit building services, where no separate power supply is needed

If the device needs to talk to a PLC or a cloud platform, IO-Link is worth checking. It's a standardised, bidirectional interface for intelligent control and monitoring, independent of the classic supply voltage.

Mounting, and what it needs to survive

Horizontal, vertical, bracket, pole, ceiling or panel mount each change the direction and reach of the signal, so the mounting type has a direct effect on how visible or audible the device ends up being.

Two things that get missed:

•     In high-vibration environments, mount the device closer to the surface. Pole mounting looks appealing for visibility, but it also transmits vibration straight into the device.

•     Match the IP rating to the environment, not just the location. Most Auer Signal devices are IP66 or IP67 rated, with an IK impact rating on top for exposure to shock and knocks.

For machine builders specifying into harsh conditions, that means checking the rating against the site conditions.

What's being signalled, and to whom

This decides the colour. Red signals danger or the highest warning level. Amber or yellow signals a warning or a critical situation building. Green signals a normal or ready state. Blue, white, turquoise and magenta carry no fixed meaning and can be assigned as required, useful where red, amber and green are already in use elsewhere on the same line.

Getting the visual signal right

The lighting function should match the urgency:

•     Strobe gets the highest attention and suits hazard warnings or machine faults

•     Flashing suits situations that need action but aren't dangerous, like a machine needing a refill

•     Steady suits normal status indication

•     Multifunction and multicolour beacons combine several of these in one device, useful where panel space is tight

LED is now the standard light source, for good reason: efficient, long service life, low maintenance. Xenon is still available on select models where a specific application calls for it.

Getting heard

Sound drops by 6dB every time the distance from the device doubles. Volume needs to be judged against both the ambient noise and the distance to the person who needs to hear it.

•     Piezo buzzers are compact and reach up to 105dB, with a limited range of tones

•     Multi-tone sirens reach up to 120dB and can reproduce standardised alarm tones, including AS1670 for the Australian market

•     Horns reach up to 112dB and can be directional, useful for controlling where the sound goes

One device, or two

A visual signal alone can be missed if it's facing away from the operator. An audible signal alone can be hard to trace back to the right machine in a busy plant. Combining a primary signal with a smaller secondary indicator solves both problems, and several Auer Signal ranges support it without needing two separate systems.

Certification worth checking

For most Australian applications, the certifications that matter most are the ones already covered above: IP and IK ratings for the environment, and ATEX certification if the device is going into a potentially explosive area, such as a petrochemical site or a mine. Auer Signal's broader certification set (CE, UL, RoHS, REACH, ISO 9001) reflects the international standards their manufacturing meets, worth knowing if a project has export or multinational compliance requirements.

Worth getting right the first time

Get clear on what needs to be signalled and the environment it's going into, and the mounting, colour, lighting function and certification requirements tend to follow from there.

If you're specifying a signalling device for an upcoming panel, machine or plant build, our team can work through it with you before you commit to an order.