Seismic Shutdown Integration for Industrial & Controls Engineers
Why process facilities need seismic shutdown integration
Industrial sites carry risks that compound in an earthquake. Gas supply, high-pressure steam, rotating machinery, chemical processes, and precision equipment all present hazards if an earthquake strikes mid-operation. The risk isn't just physical damage — it's the cascade: a lathe under load thrown against a workpiece, a boiler that doesn't shut down, a conveyor that keeps running while the building structure is assessed.
Automatic seismic detection gives your safety shutdown system the earliest possible trigger — before the destructive S-waves arrive. The MK6 detects the faster P-waves and fires its relay within 10 milliseconds, giving controlled shutdown sequences a head start.
Relay output — what you're working with
The MK6 uses an OMRON LY2 relay with two independent changeover contacts:
- Contact rating: 10A at 230V AC / 3A at 24V DC resistive
- Configuration: 2 × changeover (N/O and N/C available on each output)
- Operation: relay changes state within 10ms of first qualifying exceedance
- Hold time: relay held for 8 seconds after last threshold exceedance — prevents premature re-energisation during aftershock sequences
- Terminal strip: clearly labelled Out 1 and Out 2 with Com, N/C, N/O on each
The two independent outputs allow simultaneous triggering of different systems — for example, gas valve isolation on Out 1 and PLC input or emergency stop on Out 2.
Full wiring diagrams and terminal strip layout →
Set the threshold to match your site
Sensitivity is set via DIL switch on-site — no tools required beyond a small screwdriver. Five settings:
| Setting | Acceleration | Typical use |
|---|---|---|
| 1 | 0.012g | Maximum sensitivity — any detectable seismic event |
| 2 | 0.025g | High sensitivity — minor earthquakes |
| 3 | 0.050g | Moderate — significant local events |
| 4 | 0.100g | Low sensitivity — larger potentially damaging events only |
| 5 | 0.200g | Minimum — major events only, high false-trigger tolerance |
For industrial environments with background vibration — heavy machinery, forklift traffic, compressors — a higher threshold (0.100g or 0.200g) avoids nuisance trips. For precision equipment where any seismic event warrants shutdown, lower settings are appropriate.
Designed for P-wave detection
The MK6 monitors all axes of ground acceleration. Frequency response is flat from 2–10 Hz (±3 dB), 10 dB down at 20 Hz — matched to the frequency content of P-waves from regional earthquakes.
This is an electronic sensing system with no moving parts. Unlike passive mechanical seismic valves, it does not require physical displacement to trigger and does not require manual reset after activation.
Power options and physical spec
AC variant: 230V ±10%, 50Hz, 3VA. Internal NiCad battery backup maintains operation for up to 24 hours under mains failure.
DC variant: 12, 24, 110, or 230V DC from a no-break power supply. No internal battery. Suited to battery-backed plant and remote installations.
Physical:
- Cast aluminium casing, white polyester finish
- 290 × 220mm base, 90mm high, 3kg
- Two M16 cable entry holes
- Mounted on concrete foundation via single 6mm masonry anchor
Supply direct from the NZ manufacturer
We supply direct to controls integrators and industrial facilities across New Zealand and Australia. Contact us with your power supply requirements and application — we'll confirm the right variant and lead time.
Lead time is typically one to six weeks depending on quantities.