HMI

An HMI is often the single biggest factor in how quickly an operator can be trained on a new automated cell, and how quickly they can respond when something goes wrong. A well-designed HMI shows a clear fault message and a suggested next step; a poorly designed one shows a cryptic code that only the original integrator can interpret, which can mean a line sits stopped waiting for a support call rather than for an operator to fix a jam.

For manufacturers investing in automation, it is worth treating HMI design as a real requirement to specify up front, screen layout, alarm wording, and language options, rather than an afterthought left entirely to the integrator’s default templates.

An HMI runs on a dedicated industrial touchscreen panel, or occasionally a standard PC, and connects to the cell’s PLC over an industrial network to read and write specific data points, known as tags. The HMI software is used to build screens, often organised as an overview screen, individual station or axis screens, an alarm history screen, and a settings or recipe screen, each pulling live values from the PLC and, where the operator has permission, writing values back, such as a changed setpoint or a manual jog command.

Alarms are usually configured with priority levels, so a critical safety fault is presented differently from a minor low-stock warning, and many systems log alarm history for maintenance review. On robot cells specifically, the HMI is often the only interface the day-to-day operator touches, with the robot’s own teach pendant reserved for programming and maintenance staff, this separation keeps routine operation simple while protecting the more technical robot programming from accidental changes.