1 Introduction

Industries rely on automation to increase production rates and overall efficiencies. To raise the productivity, companies are deploying robots in factories and humans continue to work alongside these machines. As a result, employees are exposed to new types of hazards that need to be regulated to provide personal safety.

To show that robots meet the safety requirements, prior to being released to the market, each product must go through a safety assessment. Assessments must show that machines meet the minimum and regulated safety requirements. Making sure that the product is safety-compliant is usually a long and complex procedure, increasing the overall design cost, robot size, and time-to market.

This white paper offers a simplified explanation of the process needed to follow to safety assess a motor drive. The main standards used, the types of architecture, and selection of devices is described, helping to accelerate the system design process.

For this specific document, a new safety concept of a single-channel motor drive design is used as baseline. This safety concept provides a block level concept of how to achieve Category 2, Performance Level 2 (Cat 2, PLd) per ISO 13849 or Safety Integrity Level 2 and Hardware Fault Tolerance = 0 (SIL 2, HFT = 0) per IEC 61508 standard and it is intended to help the reader meet the safety requirements in a cost-effective manner. As an example, this white paper refers to the standard ISO 3691-4 which focuses on industrial trucks such as autonomous mobile robots (AMRs); however, the same procedure can be used with any other machine that requires Cat 2, PLd.

This concept uses TI's latest high-performance motor control C2000™ real-time controllers and PMICs which both include on-chip safety functionality. By using this product family, design concepts, and additional TI available safety resources, designs can achieve a lower BOM implementation of the overall system and reduce the time to market.