“Show me a plant with a poor safety record, and I’ll show you a plant that has lots of other performance issues as well. I have never seen a high-performing plant that had a poor safety record.”

  • Fast, Larry E. The 12 Principles of Manufacturing Excellence. CRC Press, 2012.

โš ๏ธ๏ธ The High Cost of Equipment-related Safety Incidents

We all have a vested interest in workplace safety, which is, without doubt, a foundational element of a sound business. Tangentially tied to the human cost of injury, death, and hardships endured by affected workers’ families are the costs associated with regulatory noncompliance, increased health insurance and workers’ compensation costs, and decreased productivity. Plants with poor safety records consequently struggle with time away cases, decreased worker engagement, and increased reliance on overtime or temporary workers.

 

Manufacturers and their equipment suppliers must share an environment and a culture that fosters a safety mindset. According to the Bureau of Labor Statistics (https://www.bls.gov/iif/), contact with objects or equipment averaged 30% of workplace fatalities in manufacturing between 2016 and 2020. For non-fatal injuries involving days away from work in 2020, 33% of safety events were due to being struck, caught in, or compressed by an object or equipment.

 

๐Ÿ‘ทโ€โ™‚๏ธ Our Safety Path

As a supplier of automation machinery of exceptional quality, MEMCO takes seriously its responsibility to deliver safe, reliable equipment that adheres to industry standards and best practices.

  • Robotics: We follow “inherent safe design” guidelines and protective measures (ANSI/RIA R15.06) that eliminate or adequately reduce risks associated with industrial robots and robot systems. These include technologies such as FANUC’s Dual Check Safety (DCS) system, which makes safe operating distances (ISO 13855) in a smaller footprint possible.
  • Automation: We meet the requirements and follow recommendations for the design and integration of safetyโ€related parts of control systems (ISO 13849) in automated machinery with Category 3 architecture for electrical and control circuitry. This provides a redundant structure such that no single component failure causes the loss of protection.
  • Component selection: We source electrical and mechanical devices and controllers readily available in the market and widely used in the industry. These parts meet the industry standards above (Category 3 compatible) and are produced by suppliers with a long track record of reliability, service, and support.
  • Testing and validation: As a matter of sound engineering practice, we complete rigorous acceptance testing at our shop and the customer’s site, meeting mutually agreed-upon success criteria.

 

๐Ÿš€ MEMCO Is Your Safety Partner

MEMCO seeks to be a key partner in the manufacturing sector’s safety improvement journey. Contact us and see how we can help accelerate your industrial transformation strategy.

๐ŸŒ An Overview of Safety Standards

Manufacturers must remain focused on operator safety as they continue to increase automation in their factories. ISO 13849 and IEC 61508 lay out the requirements for the safety-related parts of control systems (SRP/CS) and electrical/electronic/programmable electronic safety-related systems, respectively, for high demand and continuous modes of operation.

๐Ÿ”Œ Single vs. Dual Channel Structures

Safety circuits are vital components in automated machinery, designed to protect personnel and equipment from potential hazards. The ISO standard defines single-channel and dual-channel (or redundant) structures for electrical safety circuits, which are broken up into categories.

  • Category B: Category B is a single-channel circuit at the most basic performance level, using components that meet typical circuit conditions such as voltage and current ratings. These components must be suitable for the application and given environment. A single fault in the safety circuit could compromise the safety function of the device.
  • Category 1: Category 1 is similar to Category B in function but uses “well-tried safety principles” and “well-tried components” recognized by ISO or tested by their manufacturers to meet a component safety standard.
  • Category 2: This category employs periodic scans of the system to detect faults. The machine’s control system monitors the safety functionality and halts operation if a fault is detected. A loss of safety function could happen between scans.
  • Category 3: Category 3 is a dual-channel structure where a single fault in the circuit would not cause a loss of safety function due to redundancy. A comparison between single- and dual-channel structures is shown in Fig. 1.
  • Category 4: Category 4 is of the highest safety reliability, combining the structure of Category 3 with onboard diagnostics to monitor for faults. This category of safety circuit can maintain function with an accumulation of faults.

 

Fig 1. A typical emergency stop (e-stop) push-button with one normally open (NO) and two normally closed (NC) contacts. A single-channel structure (a) with one fault (failure to open) would result in a loss of safety protection, while the dual-channel structure of Category 3 or 4 (b) has a redundant input signal.

๐Ÿค– Safety programmable logic control (PLC) devices

Safety PLCs have the benefits of 1) reducing the size and complexity of wiring typically found with traditional safety relays and 2) simplifying future expansion and modification since physical infrastructure changes (e.g., rewiring and adding panels/components) are minimized. They are designed to provide control and safety measures for automated equipment and include programming dedicated to error detection. Safety PLCs continuously monitor input signal status to detect malfunctions and are held to high standards for software integrity and lifecycle testing.

๐Ÿš€ MEMCOโ€™s Delivers Safety and Reliability

MEMCO’s controls engineering team designs automation and robotic systems with your operators’ safety in mind using dedicated safety PLCs, dedicated safety input-output (I/O) modules, the latest robot safety system technologies, and Category 3-rated devices.

Contact us (https://memco.ai/contact) and see how we deliver safe, reliable machinery that complies with standards and best practices of the automated manufacturing industry.


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References

  1. ISO 13849-1:2023, Safety of machinery – Safety-related parts of control systems – Part 1: General principles for design. International Organization for Standardization (ISO).
  2. IEC 61508-1:2010, Functional safety of electrical/electronic/programmable electronic safety-related systems – Part 1: General requirements. International Electrotechnical Commission.