343.1 PL/Category intent (plain)

Target performance levels that match risk. Plain rules help non-specialists keep automatic HVM bollard circuits robust.

In simple terms, “PL” describes how reliably a safety function prevents harm over time; “Category” describes the circuit architecture used to achieve that reliability. For automatic HVM lanes, choose a level that reflects credible hazards: crush, impact, and trapped pedestrians. Start with a task-based risk review, then map risks to safety functions (e.g., inhibit raise on obstruction) and select a Category that tolerates single faults without losing the function.

Where operations are frequent or public-facing, aim for architectures that detect faults before restart. Tie PL choices to your interlock matrix (352 Interlock matrix) and to fail-states defined in 355 Fail-safe/secure states.

343.2 Safety inputs inventory

List loops, beams, edges, mats, E-stops (344–345). Inputs protect users around a crash rated bollard post.

Typical inputs include vehicle induction loops, photo-eyes (photocells), pressure edges/mats, gate position switches, and emergency stop stations. Each input should be defined as a safety function (what it must prevent), its required response (inhibit, stop, alarm), and its test method (manual or auto at power-up). Document zones (near-bollard, queue/hold line) so you do not create unprotected “gray” areas.

Keep the list synchronized with 523 I/O List Template and show each sensor in the interlock matrix. Field device selection lives in 345 Field Devices; placement ties to 232 Spacing rules.

343.3 Circuit topology examples

Use dual-channel, monitored circuits with safe relays. Topologies prevent unsafe motion of automatic HVM bollard units.

For most lanes, dual-channel inputs wired to a safety relay (or safety PLC) with cross-monitoring provide a robust baseline. Each channel is independent; a single fault (e.g., broken wire) is detected before enabling motion. Use force-guided relay contacts for feedback and employ start-checks that verify input agreement before allowing raise/lower commands.

Where multiple posts share one drive, design so any single safety trigger inhibits movement of the affected post set. Include PLC/Controller watchdogs and movement timeouts, and reflect these in 342 Control logic. Interfaces to BMS/SCADA reporting should be read-only for safety states.

343.4 Redundancy & diagnostics

Redundant paths and cross-monitoring detect faults early. Diagnostics shorten HVM bollard downtime.

Redundancy prevents single points of failure; diagnostics reveal hidden faults. Implement channel comparison (A ≠ B) with latching faults, cable break/short detection in sensor loops, and periodic “muting” tests that prove beams and loops. Trend nuisance trips and create alerts via remote fault logging & health pings so maintenance can preempt failures.

Publish a minimal operator dashboard with clear icons and plain text. Map diagnostic codes to a runbook and keep spares for common failure items (relays, photo-eyes) per 854 Warranty & spares policy.

343.5 E-stops & safe stops

Define stop categories and locations (354). Stops must default the crash rated bollard lane to a safe state.

Emergency stops (E-stops) must be prominent, reachable, and clearly labeled. Use stop categories that fit the hazard: an immediate removal of power for a crush risk, or a controlled stop where drive systems require deceleration. Align stop behavior with EFO and with fail-safe/secure definitions so the lane never opens unintentionally. Mark stewarded positions and the clear-gap line to avoid crowding at the post head.

In UAE projects, confirm E-stop count and locations during SIRA design review—see SIRA Bollards (UAE). Record choices in the FDS and cross-check during SAT witness (638).

343.6 Test intervals & proof tests

Routine tests prove function (631–636). Testing sustains automatic HVM bollard reliability.

Define two layers of testing: (a) automatic start-up tests (prove beams, input agreement, relay feedback) and (b) scheduled proof tests performed by trained staff. Use weekly quick-checks (photo-eye break, loop simulate) and monthly functional drills (raise/stop/lower under controlled conditions). Record results with date, tester, and evidence per 631 Pre-commission to 636 Performance & Duty Tests.

Failures should latch with a clear reset process. Only allow reset after the cause is corrected and the proof test rerun—make this explicit in the operator workflow.

343.7 Bypass/maintenance modes

Controlled bypass with indicators and timers (525). Bypass must not widen HVM bollard gaps beyond acceptance (232).

Maintenance happens, but bypass must be safe, obvious, and time-limited. Use key-switch enable with a flashing indicator, on-screen message, and an auto-expiry timer. In bypass, raise commands are inhibited unless a steward actively commands motion (deadman). If a post is removed or locked down, verify the remaining array still meets the clear-gap rule (232).

Document bypass in the FDS and the site LOTO procedure (725). After works, use the reset-to-normal checklist (see 540-series workflows) before handing back to operations.

343.8 Wiring & labeling rules

Color codes, ferrules, and segregation (347, 527). Clean wiring prevents errors that could affect a crash rated bollard.

Keep safety wiring separate from power and non-safety I/O. Use consistent colors, numbered ferrules, and durable labels on both conductors and devices. Terminate safety channels on distinct terminals and route through dedicated glands. Follow enclosure and cable practices in 347 Enclosures & Cabling and 527 Panel Wiring Standards.

For outdoor, hot, or coastal sites, select IP-rated enclosures and glands matched to environment; see 516 Enclosure Protection and 363 Environmental durability.

343.9 Acceptance criteria

Document pass/fail thresholds and evidence (716, 638). Criteria secure approvals for automatic HVM bollard safety.

Acceptance is a checklist with evidence: (1) all safety inputs proved, (2) stop categories verified, (3) diagnostics and latching faults demonstrated, (4) bypass mode behavior and expiry tested, and (5) documentation completed (I/O list, interlock matrix, test records). Capture photo/video evidence per 716 Evidence capture standards and close under 638 SAT / Witness.

Summarize residual risks and operating limits in the O&M pack and train operators on emergency and recovery workflows (see 547 Emergency modes).

343 Safety circuits for automatic HVM Bollards — FAQ