The controller runs the machine; the HMI is how humans run the controller. Rockwell's answer is FactoryTalk View — ME on PanelView Plus terminals at the machine, SE for distributed plant-wide SCADA — talking to Logix through FactoryTalk Linx. The superpower: displays bind directly to controller tags. No register map, no middleman.
A PanelView Plus screen for a mix tank, wired to the controller tags on the right. Press START — watch HMI_StartPB pulse true, the controller's logic latch Pump_Run, and the level climb. Past 85 % the tag-based alarm fires and the banner takes over. Then flip to 🔧 Design mode to see what the screen really is: graphic objects with tag bindings.
That yellow chip syntax — {::[Mixer]Tank_Level} — is a direct tag reference: shortcut name in brackets, then the live Logix tag, browsed straight from the controller's tag database. Rename the tag in Studio 5000 and View's cross-reference finds every display that breaks. Compare that to the register-mapping ritual every non-Rockwell HMI still performs.
🖥️ View ME (Machine Edition). One operator station: runs on PanelView Plus terminals (or a PC) as a compiled .mer runtime. Standalone, robust, lives at the machine. Most plants are full of these.
🏭 View SE (Site Edition). Distributed SCADA: a FactoryTalk Directory, HMI servers with redundancy, clients anywhere on the network, plant-wide alarming and history. When twelve screens must agree on one truth, it's SE.
🔗 FactoryTalk Linx & shortcuts. The comms layer. You define a shortcut (a named pointer to a controller) once; every tag reference rides it. Re-point the shortcut at a new PLC and the whole application follows.
⬓ Momentary buttons need PLC logic. A momentary PB writes 1 while pressed, 0 on release — so the latch must live in the controller (seal-in or ALMD-style logic). Never use a maintained HMI button as the only thing keeping a machine running: if comms drop, the controller must decide, not the screen.
A plant has twelve machines, each with its own PanelView Plus terminal showing only that machine's status. No shared history, no central alarm view needed. Which FactoryTalk View edition fits?