The Headless HMI Requirement
Engineers building wireless operator interfaces around tablets frequently ask for a "screenless" C-more: the HMI runtime and communications engine packaged as a DIN-rail box inside the cabinet, serving pages to the C-more iPad app rather than driving a local touchscreen. The driver is cost and panel space: the application needs remote screens, not a mounted display that sees little use. A secondary benefit is resolution — a headless server is not constrained by the physical panel's display resolution, so screens can render at full quality on large desktop monitors or high-resolution tablets.
Development workflow is the key argument for staying in the C-more ecosystem: a headless engine would use the same C-more programming environment as the current touchscreen line, so existing tag databases, screen objects, and PLC communications drivers carry over unchanged.
AutomationDirect's Direction: Controller-Served HMI Content
AutomationDirect has indicated that a dedicated headless HMI appliance is not the planned path. Instead, the stated direction is for the PLC itself to serve HMI content — beginning with simple textual screens and expanding to more complex content over time, potentially through more than one delivery mechanism. A controller that serves HMI pages delivers the same practical result as a headless HMI: no panel to purchase, mount, or maintain.
Until controller-served content matures, the supported architecture for iPad-based operation remains a physical C-more panel acting as the screen server to the C-more remote app. The panel handles PLC communications and screen rendering; the tablet is a remote viewer. Note that a screenless device with software-rendered screens viewed on arbitrary monitors blurs the HMI/SCADA boundary — it still requires HMI-like hardware, but the display layer is entirely software, which is why PC-based SCADA-class tools compete in this space.
Alternative Architectures While No Headless Option Exists
| Approach | Server Hardware | Client | Trade-off |
|---|---|---|---|
| C-more panel + remote app | Physical C-more touchscreen | C-more iPad app | Works today with the standard C-more programming environment, but requires buying and placing a panel that exists mainly to serve remote screens |
| Controller-served HMI content | PLC CPU | Browser or app client | No HMI hardware at all; announced direction, initially limited to simple textual screens |
| PC-based HMI (e.g., Advanced HMI) | Industrial PC or desktop | Local monitor / remote desktop | Free and not limited by panel resolution, but simple applications take more development effort than the C-more environment |
Decision path: if wireless tablet access is the requirement now, deploy the smallest C-more panel that meets the communications and screen-count needs and use it purely as the remote app server. If the project can wait and the content is simple text status, track the controller-served HMI roadmap. If development effort is acceptable and you want large-monitor rendering, evaluate a PC-based package such as Advanced HMI — its drivers target the same PLC families, but budget more engineering time per screen than the C-more drag-and-drop workflow.
FAQ
Can a C-more panel serve screens to an iPad?
Yes. A physical C-more touchscreen acts as the screen server, and operators view and interact with those screens remotely through the C-more iPad app. The panel handles all PLC communications; the tablet functions as a wireless remote display.
Does AutomationDirect offer a headless, DIN-rail C-more engine?
No headless C-more hardware product has been offered. AutomationDirect's stated direction is for the PLC controller itself to serve HMI content, starting with simple textual screens rather than a dedicated screenless HMI appliance.
What are the alternatives to buying a C-more panel just to serve remote screens?
Two paths exist: use the PLC's own served-content capability once available for your content complexity, or run a PC-based HMI package such as Advanced HMI on an industrial PC. The PC option is free and unconstrained by panel resolution but requires more development effort for simple applications.