Conveyor safety

MDR conveyor safety, designed to SIL 2 / PL d

E-stops, pull cords, guard interlocks, and safe removal of MDR motor power. Unless your risk assessment or company standard says otherwise, we design MDR conveyor safety functions to SIL 2 / PL d and verify them before handover.

Discuss a safety scope How we verify it

Why SIL 2 / PL d is our default

Most MDR conveyor hazards are pinch points, nip points at transfers, and unexpected start-up. For these, a two-channel design (Category 3) reaching PL d under ISO 13849-1, or SIL 2 under IEC 62061, is a common and defensible target. We use it as the starting point.

The required level still comes from the risk assessment. If yours sets a different Performance Level, or your company standard does, we design to that instead. If there is no risk assessment yet, we can help you work through one.

A level is only claimed once it has been calculated with the real components and tested.

Safety functions

What we design into the conveyor

Each safety function is listed with its trigger, its stop zone, its target level, and how it will be tested.

E-stops

Two-channel E-stop stations at operator positions, transfers, and access points, monitored by a safety relay or safety PLC.

Pull cords

Two-channel pull-cord switches along long runs where an operator can reach the conveyor, with cord tension and switch spacing per the manufacturer.

Guard interlocks

Interlocked guards and gates at transfers, lifts, and drive areas, with locking where run-down time requires it.

Safe power removal

MDR motor power removed through redundant contactors with feedback monitoring (EDM), or a safety-rated input where the MDR platform provides one.

Stop zones

Stops grouped into zones that match the risk assessment, so one E-stop stops the hazard without shutting down the whole building.

Start-up warning

Horns and beacons before motion where ASME B20.1 calls for them, such as when the whole conveyor can’t be seen from the start point.

Would you like to know more? Standards we design conveyor safety around
ASME B20.1

Safety standard for conveyors and related equipment: guarding, emergency stops, and start-up warnings.

ISO 13849-1 / IEC 62061

Safety-related parts of control systems. Performance Level (PL) and SIL are calculated from architecture, diagnostic coverage, and component reliability data.

ISO 12100 / ANSI B11.0

Risk assessment principles that set the required level for each safety function.

NFPA 79

Electrical standard for industrial machinery, including stop categories and control circuits.

OSHA 29 CFR 1910.147

Lockout/tagout: energy isolation points laid out and labeled for service work.

Verification

How we verify it

Paperwork and testing are part of the safety design, not an afterthought.

  • Safety function list

    Every function listed with its input devices, logic, output devices, stop category, stop zone, and target level.

  • Calculation

    PL or SIL calculated with SISTEMA (ISO 13849-1) or to IEC 62061 using manufacturer data for each device, including contactor B10d values and switching rates.

  • Fault testing

    At FAT and on site we test single faults: an opened channel, a welded contactor simulated through EDM, a cross-fault where the device detects it.

  • Records

    Test results recorded for each function and included in the closeout package, with the calculation report.

  • Open items, stated plainly

    Anything we can’t verify, such as a customer-supplied device without safety data, is listed as an open item, not assumed.

Your inputs

What we need from you

  • Risk assessment

    Your existing risk assessment, or time with your safety lead to build one for the conveyor.

  • Company standard

    Any internal safety standard, preferred safety PLC or relay, and approved E-stop and pull-cord hardware.

  • Interfaces

    Other equipment on the safety circuit: lifts, robots, palletizers, doors, or fire system inputs.

Next step

Need conveyor safety designed or reviewed?

Send the layout, your risk assessment if you have one, and what the safety circuit looks like today. We’ll reply with questions and a scope.

[email protected]

Mon–Fri, 9:00 AM – 4:00 PM ET · we reply within one business day
Engineering offices in Clearwater, Florida · available for Zoom meetings

Your request goes to an engineer, not a call center. Expect a reply within one business day.