Programming Safety into Machine Control Systems

From increased visibility with advanced camera systems, to alerts and operator presence features, machine safety continues to be an area of constant focus & improvement for heavy equipment OEMs.  But what are some simple ways that machine safety can be designed directly into the control system without making large investments into new components or larger machine changes? The engineering team at GS Global Resources is home to numerous IQAN® by Parker Hannifin experts who have worked across a wide range of industries and addressed many application specific safety concerns. We asked them to name some of the ways they have added safety features directly into a machine’s primary control system, including functions that limit hazardous motion, verify operator presence, and prevent unsafe startups.

Operator presence and access control

One of the most common approaches is to make machine operation dependent on operator presence. Seat switches, seat belts, door switches, and other interlocks can prevent startup or disarm the machine if the operator is not properly positioned or if an access door is open. These features are especially useful when a machine could move unexpectedly or when an open panel, door, or cab entry creates a crush or entanglement risk. The goal is simple: if the operator is not in the right place, the control system should not allow motion.

Motion and load limits

Another major safety strategy is to block certain functions when a machine is already in motion or carrying an active load. For example, in a tow truck application, you can restrict motion based on the boom angle or rotation, the outriggers or winch position, or the load state to prevent uneven weight putting the truck in an unstable situation. These features are also common in fire trucks or bucket-style equipment, where the controller can allow some actions while preventing other that would raise the center of gravity or risk a collision. In practice, this is often implemented as a functional cutout or similar safety logic.

Redundancy and validation

Safety systems are stronger when the controller does not rely on a single sensor or signal. You can integrate redundant inputs such as dual position sensors, dual CAN paths, and paired outputs that are checked in reference to each other before the system accepts a signal as valid. That same idea can also be applied to joysticks, pedals, steering inputs, and other operator controls. If two signals don’t match, the machine can default to a safe state rather than trusting a potentially incorrect signal.

Safe startup logic

Startup interlocks are another important layer of protection. The machine can be programmed to confirm that the pedals, joysticks, or other controls are in neutral before enabling motion. It can also block the output until the controls return to a safe position. These features prevent accidental movement when an outside object, for example the operator’s jacket, is accidentally resting on a control that could start a function. A clear message on the display can also alert the operator and explain why the machine is not starting, which reduces confusion and repeated unsafe attempts.

Zone detection and avoidance

Programmable safety can also protect people and equipment around the machine. Some examples of this are sensors that detect if a door is open, camera-based detection of people or objects, or other avoidance systems that keep a boom, bucket, or rotating structure from colliding with outside objects. These zone controls are especially valuable on machines like cranes or fire trucks, where the application can require the boom to lift before it swings into certain areas. That kind of logic can turn geometry and position data into an automatic safety boundary.

Safety communications and controllers

Before you can program logic and other features into the system, you need to start with safety-rated communication and controller options, including CAN open safety, J1939 safety, and functional safety controller modules. These systems add redundancy at the component level so safety decisions are based on more reliable data paths and rated function blocks. For OEMs, that means safety can be built into both the hardware itself, as well as the program logic.

Interested in learning specific IQAN programming techniques and tools? We have a library of on-demand targeted training videos you can look through, or you can sign up for our in-person IQAN training sessions where our instructors go over the basics of the creative suite and answer your specific machine questions.