Custom Human-Machine Interface for operators on the shop floor, at the machine or in the field. Web-based or on industrial touchscreens, with live process data, alarms and recipe management, integrated with your PLCs via OPC UA, Modbus or MQTT.
An HMI (Human-Machine Interface) is the screen an operator uses to control a machine or installation. In practice it is usually a 15 to 21-inch industrial touchscreen mounted beside the line, but increasingly also a tablet the operator carries around, or a browser page on a workstation in the control room.
Functionally, an HMI displays live process variables (temperature, pressure, speed, fill level) and provides buttons to start, stop or reset the machine. On top of this sit prioritised alarms, trend charts covering the last few hours or shifts, parameter adjustments, and recipe management for different production runs or product types. The HMI pulls this data in real time from the PLC (Programmable Logic Controller) that physically drives the machine, usually via OPC UA, sometimes via Modbus or a manufacturer-specific protocol.
In the Purdue Reference Model, the most widely used framework for industrial automation, the HMI sits at level 2: the operator interface at the machine. Level 1 is the PLC itself, level 3 is SCADA for supervisory monitoring across multiple machines or sites, level 3.5 is the MES for production execution, and level 4 is your ERP. The higher you go in this stack, the more business logic there is and the less real-time control. A well-built HMI knows its place in that stack: operating and visualising on the shop floor, and passing context up to the layers above.
We build custom HMI software when the standard packages from Siemens, Rockwell or Schneider don't quite fit. For example, because you want a single interface across different PLC brands, because operators move around with a tablet, or because the interface needs to integrate deeply with your MES system and ERP. For the horizontal integrations with higher-level systems, we often build API integrations between HMI, MES and ERP, so production orders, quality records and machine events flow through automatically.
Depending on where the interface needs to run, how many machines and sites it spans, and how deep the integration with your upstream systems needs to go.
An interface for a single machine or installation, running on an industrial touchscreen or a local browser. Live process data from the PLC, alarm handling, basic trends and operator login with role management. Suitable as a replacement for an outdated proprietary HMI or as the interface on a new line.
A browser-based HMI that operators can open on a tablet, phone or workstation. One codebase for multiple devices, push notifications for critical alarms, and role-based access to machine clusters. Operators can move about with a device rather than being tied to a single panel.
One HMI platform across multiple PLC brands (Siemens, Rockwell, Beckhoff, Omron) or multiple production sites. A unified data layer via OPC UA and MQTT, a branded interface in your look and feel, and integrations with MES, ERP and historian systems. The bridge between the plant floor and the office.
A production-ready HMI platform, plus the documentation and integrations you need to manage and extend it yourself.
We do not replace Siemens WinCC, Rockwell FactoryTalk or Schneider Vijeo for small, simple jobs; they excel at that. It is worth considering custom development in the situations below.
You have Siemens PLCs alongside Rockwell, or Beckhoff alongside Omron. A single-vendor HMI forces everything into their ecosystem. A custom HMI talks to all of them via OPC UA and gives the operator one user interface.
The operator is not tied to one panel but walks along the line with a tablet. A browser-based HMI works on tablet, phone and workstation without you managing three different interfaces.
For OEMs and machine builders: you sell the machine, but the standard HMI looks like the PLC vendor's. A custom HMI in your own industrial UX makes the machine recognisably yours.
The HMI needs to pull production orders from the ERP, write quality data to the MES, and push maintenance signals to the CMMS. That kind of horizontal integration is not standard in vendor packages.
OPC UA (Open Platform Communications Unified Architecture) is the industrial standard protocol that has become the dominant way to talk to a PLC over the past ten years. It is vendor-independent: an OPC UA client talks to a Siemens PLC just as well as to a Rockwell or Beckhoff, provided the PLC publishes a UA server. For modern PLCs this is built in as standard; for legacy controllers we build a gateway that translates Modbus, Profinet or a manufacturer-specific protocol into OPC UA, so the HMI only needs to speak one language.
We also use MQTT for publish/subscribe scenarios. It's especially useful if you monitor machines remotely, or if data needs to reach multiple consumers (HMI, MES, historian, dashboard) without each one opening its own connection to the PLC. For field-level connections, Modbus TCP is still often needed, particularly on older installations or small sensor modules where OPC UA is overkill.
A typical custom HMI tech stack looks like this: a web front end in React or Vue for the operator interface, a Node.js or Python backend that handles PLC communication and normalises data, a time-series database (InfluxDB or TimescaleDB) for historical trends, and WebSocket or Server-Sent Events for real-time push to the browser. For scenarios where machines also need to be accessible remotely, for example engineers carrying out on-site maintenance, we often connect the HMI to an IoT app that shows the same data on a phone or tablet, with push notifications for critical events.
With OneDayBuild, we turn your idea into something tangible in one day for €1,150, so you can see whether further development is worth the investment. Decide to go ahead with the full build? Then we credit the full cost.
Explore OneDayBuild →The Dutch and German plant-floor landscape is largely dominated by a handful of HMI packages: Siemens WinCC (often paired with a Siemens TIA Portal PLC), Rockwell FactoryTalk View (Allen-Bradley environments), Schneider Electric Vijeo Designer (Modicon and Magelis), Wonderware InTouch (now AVEVA), Inductive Automation Ignition (vendor-neutral, web-based), B&R and Beckhoff TwinCAT HMI. These packages are mature, well documented and, in many cases, the right choice.
This is where we come in, as these packages have limitations: they are typically tightly bound to their own PLC ecosystem, their web clients are often licence-bound and not always truly mobile-friendly, and their look and feel is generic. For a single-vendor, single-machine HMI on an industrial touchscreen, the standard package is the right choice. For a multi-vendor, mobile or branded scenario, the extra investment in custom development often outweighs the licensing and flexibility constraints in the long run.
A specific example where custom development wins: you are a machine builder selling installations to customers worldwide, and you want the HMI on your machine to be recognisably yours, not the PLC supplier's. We then build a branded thin-client or web HMI that carries your look and feel, while the PLC choice can vary per customer or per machine. The same applies to manufacturers with a mixed PLC shop floor who want to spare operators from switching between different vendor interfaces.
A conversation in which we understand which machines you have, which PLC brands run them, what data needs to appear on screen and which compliance requirements apply. Where possible, we walk the production floor with you to observe the operator flow.
We inventory the OPC UA, Modbus or MQTT tags the HMI needs, and sketch the initial screen flow with your operator and process engineers. At the end you have a scope, a plan and a clickable prototype.
A working build every two weeks that you can test against a staging PLC or a PLC simulator. Operators test along from the first sprint, because an HMI that looks good in a meeting can still prove awkward on the floor.
Phased go-live on one line, then rollout to the rest. Operator training, a short video tutorial and a runbook for your IT and OT teams. Afterwards, ongoing maintenance for security updates and further development.
What clients usually want to know before starting a custom HMI project.
A free, no-obligation introductory call of half an hour. We listen to your machine park, your PLC landscape and your operator workflow, and give direction where it's useful to you. Often this is followed by a short walk-through on the shop floor, as nothing reveals more than the real working environment.
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