Safety-Integrated Motion Control Allows Safety and Productivity to Co-Exist

Ultimately, the objective of any manufacturing operation is to produce product. Accordingly, corporate goals often focus on efficiency, quality and productivity. While some companies view safety as a necessary evil or, worse, a costly drain on productivity, top-tier manufacturers rank safety as a priority and embed it deeply into the culture of the company. Furthering their efforts, motion control systems with integrated safety functions can help enhance plant and operator safety while also boosting productivity.

What is Motion Control?

Motion control technologies, used throughout the manufacturing industry, function as the brain of the automation system. Together, multiple components such as microcontrollers, programmable logic controllers (PLCs) and motion controllers, create a motion sequence that controls speed, position and torque.

Within a motion automation system, an input device or software program relays pre-set instructions to the motion controller. The motion controller signals the drive, which controls the motor. Based on the inputs, the motor will then produce linear or rotary motion at the specified speed and torque. Additionally, motion control sensors monitor the speed, torque, temperature, vibration and current to ensure that the operation is running as intended.

Motion Control Advancements Boost Safety and Productivity

Traditionally, hazardous machinery was physically guarded, which meant operators had to bring production to a halt to attend to a problem, resulting in unplanned downtime. Even worse, in an effort to avoid downtime, operators were often tempted to leave the machine running and circumvent the barrier, resulting in injury.

To avoid these scenarios, safety functionality may be added to machines via hardware and electro-mechanical safety components that automatically shut down equipment when hazards, or trigger events, are detected. For example, a machine may come to a stop if the associated safety light curtain is breached. While such safeguards are necessary, these outages result in unplanned downtime and productivity losses when equipment or lines are shut down due to detected hazards. Additionally, the sudden stop can wreak havoc on the internals of the machine, as well as the product being handled, resulting in costly maintenance, downtime and scrap. While safety devices such as these do a thorough job of protecting operators, they are unable to decipher whether the trigger event is a true emergency that requires a complete shutdown of the equipment, a hazard that could be avoided by slowing machine speed or a false alarm.

Seeking a way to incorporate machine safety without negatively affecting productivity, safety-integrated motion control systems were developed. Here, rather than adding safety features to equipment after the fact, they are integrated within the motion control system’s drive, controllers or PLCs. For example, drive-integrated safety functionality performs continuous safety monitoring to allow safe stopping of the drive without disconnecting the main power, allowing faster restarts and less downtime, while reducing the likelihood of equipment or product damage. Basic drive-integrated safety functionality might include safe stopping, safe braking and motion monitoring.

This type of integrated safety can be achieved via centralized or decentralized safety controls. In centralized control, the whole application is contained within the motion or logic PLC. Decentralized safety solutions involve remote safety PLCs with safety requirements set via programmed inputs.

Inputs may include a safety sequence that controls how the machine should respond to a trigger event: Should the machine come to a complete stop or slow down at a certain rate? What is the required timeframe between the trigger event and stopping or slowing the motion? Should the entire line be involved or just one piece of equipment?

While safety functions can be packaged in different ways, one thing is certain: the advanced capabilities of today’s safety-integrated motion control systems to react appropriately to an event means that safety and productivity can happily co-exist. The benefits of incorporating safety-integrated motion control into the automation system include fewer accidents, longer equipment life, less scrap and higher overall productivity because there are fewer interruptions, less downtime and faster restarts. As a bonus, employees tend to be more productive when they feel appreciated.

Failure to embrace safety-integrated motion control to boost both productivity and safety can leave manufacturers unable to keep up with the competition. But keep in mind that just incorporating a safety-integrated motion control system on automated machinery does not ensure an accident-free facility. The technology must be employed in conjunction with a risk assessment that identifies the measures that need to be taken to avoid risks to personnel and equipment, as well as determining the possible events that could trigger the safety functionality and the way in which the machine should react to those events to avoid issues. Additional components such as safety switches and relays, lock out/tag out equipment, safety light curtains and other precautions may also be needed to meet all appropriate safety standards and regulations.

To learn more about safety-integrated motion control and how it can help enhance both safety and productivity in your facility, please contact a JHFOSTER specialist.