What Is an Industrial PC?

An industrial PC, often called an IPC (industrial personal computer), is a computer built or selected for use in industrial environments. Like other computers, it runs software and can communicate with other devices. Its hardware, mounting, and support options are intended for applications such as machine control, production monitoring, and operator interfaces.

An IPC might be a compact box inside a control cabinet, a computer built into a touchscreen panel, or a rack-mounted system. Some are fanless, have a wide operating-temperature range, or offer long product availability. The features depend on the model: an industrial label alone does not mean every IPC is suitable for every environment.

What can an IPC do on a machine?

The answer depends on the software installed and the way the system is designed. An IPC can:

• Show an operator interface with machine status, alarms, and controls.

• Collect and store production data or exchange it with other systems.

• Process images from a camera or run other applications.

• Run a software PLC, sometimes called a soft PLC: software that does the job of a programmable logic controller (PLC) and executes a control program.

One IPC may perform several of these jobs, or each job may have its own device. An IPC that displays a human-machine interface (HMI) is not automatically the controller; it might simply communicate with a separate PLC.

PLC and IPC: where they overlap

A PLC is a controller that runs a control program and works with inputs and outputs. An IPC describes a type of computer hardware. The terms often overlap because an IPC can run software that gives it PLC functionality.

In either arrangement, sensors provide information and outputs command devices. The field input/output (I/O) may be connected locally or over an industrial network. The physical PC's ports do not by themselves make it a PLC: the controller software and suitable I/O are part of the solution.

For example, a packaging machine might use a separate PLC to run the conveyor while an IPC displays production counts. Another machine might use an IPC with a software PLC runtime to run the conveyor and display those counts on the same computer.

What is a runtime?

A runtime is the software environment that executes a program on the target controller. A software PLC runtime can execute control logic on an IPC, often using familiar PLC languages such as Ladder or Structured Text. The programming tool used to develop the logic may run on a different computer.

The IPC's operating system and the controller runtime have to be configured as a complete system. Some products use a real-time environment that runs alongside or separately from the general-purpose operating system. The behavior during an operating-system restart or failure depends on the particular product and configuration; do not assume the controller will continue running.

Why timing matters

Machine control often needs work to happen within a predictable time. This is called real-time behavior: the system must respond within the timing required by the application, not merely be fast on average.

A standard desktop operating system running an ordinary application does not automatically provide the predictable timing a control task needs. A PC-based controller may use a real-time runtime, special configuration, and compatible hardware. Whether the complete system meets a machine's timing requirements must be checked for that application.

Choosing and maintaining a system

A dedicated PLC can be a good fit for a machine that needs a focused controller and conventional industrial I/O. An IPC-based system can be useful when the application also needs PC software, data processing, or several control functions on the same platform. Both approaches come in many forms; the right choice depends on the actual requirements.

Consider the environment, I/O and network compatibility, timing, availability of replacement parts, software licensing and updates, recovery after a power loss, and how the system will be maintained. Combining functions on one IPC can simplify integration, but also means a hardware failure can affect multiple functions at once.

A safety function still needs an appropriately designed safety system. An IPC or ordinary software PLC is not automatically a safety controller; use equipment and architecture suitable for the required safety function.

Key takeaways

• An IPC is industrial computer hardware; a PLC is a controller that runs control logic.

• An IPC can run an HMI, a software PLC, or other applications, depending on its software and configuration.

• A dedicated PLC and an IPC running a software PLC can both control machines through suitable I/O.

• Timing, reliability, recovery, and safety depend on the complete system, not just the hardware label.

Continue with What Is a PLC? for the basics of inputs, programs, and outputs.

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