HMIs
A human machine interface (HMI) is the screen operators use to run and monitor equipment. A well-chosen HMI shows the right information clearly, makes alarms easy to understand and cuts down on operator errors, from a single machine up to a whole process line.
HMI Options
- Touchscreen operator panels – 4" to 15"+ displays for machine-level control
- Industrial panel PCs – run SCADA and advanced visualization software
- Text displays and keypads – simple, rugged interfaces for basic equipment
- Web-enabled and remote HMIs – view and control machines from a browser or mobile device
- HMI accessories – mounting kits, cables, protective covers and software
Choosing an HMI
Start with communication: make sure the HMI supports your PLC's protocol, such as EtherNet/IP, Modbus or PROFINET. Then size the screen for the information operators need and check the panel cutout, environmental rating and sunlight readability. Software licensing and ease of programming also affect long-term cost.
Centro offers HMIs and accessories from leading automation brands and can help you pick one that works with your existing controls.
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$724.18
Subject to factory lead times
$648.30
Subject to factory lead times
$457.15
Subject to factory lead times
$256.57
Subject to factory lead times
$648.30
Subject to factory lead times
$724.18
Subject to factory lead times
$519.02
Subject to factory lead times
$339.60
Subject to factory lead times
$457.15
Subject to factory lead times
$517.47
Subject to factory lead times
$724.18
Subject to factory lead times
$648.30
Subject to factory lead times
$457.15
Subject to factory lead times
$256.57
Subject to factory lead times
$648.30
Subject to factory lead times
$724.18
Subject to factory lead times
$519.02
Subject to factory lead times
$339.60
Subject to factory lead times
$457.15
Subject to factory lead times
$517.47
Subject to factory lead times
- An HMI is a local operator interface — it displays process data and accepts operator input at a single machine or panel. SCADA (Supervisory Control and Data Acquisition) is a broader system architecture that collects data from multiple HMIs, PLCs, and field devices across an entire facility or geographic area, centralizing monitoring, historical data logging, and reporting at a supervisory level. In practice, most modern HMI panels can serve as the local interface while also feeding data upstream to a SCADA server. For single-machine or single-process applications, an HMI alone is typically sufficient.
- Most industrial HMI panels support a range of standard protocols to communicate with PLCs and controllers from various manufacturers. Ethernet-based protocols — EtherNet/IP, Modbus TCP, and PROFINET — are the current standard for new installations. Serial protocols such as Modbus RTU and RS-232/485 remain common for legacy equipment. Many panels also support OPC-UA for seamless integration with SCADA systems and MES platforms. When selecting an HMI, verify that it natively supports the protocol of your PLC or controller without requiring additional gateways or converters.
- A full HMI panel is a self-contained unit with its own processor, memory, and software environment — it runs the HMI application locally and communicates directly with PLCs. A flat panel monitor display is essentially an industrial-grade screen without onboard processing; it requires a separate PC or industrial computer to run the HMI software and simply outputs that image to the display. Flat panel monitors offer flexibility for high-performance or complex visualization applications where a dedicated PC provides more processing power than a standalone HMI. Full HMI panels are the simpler, more cost-effective choice for standard machine-level applications where a separate PC is not required.