Device LinkByte

LinkByte

This page is generated from the Unity twin. Published from _docs/context/devices/linkbyte.md — edit it there, not here. Changes made in the wiki are overwritten on the next sync.

A plain byte in each direction, with no behaviour of its own — the way to give the PLC a device Open Commissioning has no component for.

Twin device type · twin FB FB_DeviceByte · 1 instance in FG_01 · Unity component OC.Components.LinkByte

What it is

Sometimes the machine has something that is not a cylinder, a sensor or a drive: a laser module, a feeder, a piece of third-party equipment with its own protocol. LinkByte is the generic answer — eight control bits down, eight status bits up, and whatever they mean is decided by how the scene is wired.

What the PLC sees

Symbol	Meaning
ControlData.0 … ControlData.7	Whatever the scene wires each bit to
StatusData.0 … StatusData.7	Whatever the scene reports back

Because the meaning is per instance, it is stated per instance: look for the Bit mapping section on the group page that owns the device.

How the twin models it

Each control bit raises an event when it changes, and those events are wired in the Unity inspector to whatever should happen — start an animation, enable a conveyor, fire a laser. Status bits are set by whatever in the scene knows the answer.

Watch out

A LinkByte promises nothing. A cylinder reports arrival because the component measures it; a LinkByte reports only what someone wired to it. If a bit has no status wired back, the PLC gets no confirmation the thing happened — which is a fact about the real device as often as it is about the model.

In this machine

Signal — One control bit out enables the laser module; held high for 1 s it applies the mark. NO status bits - the PLC gets no confirmation that it fired.

There is 1 of them, in FG_01:

Device	Twin PLC path	Group
Y_LaserMark	MAIN.FG_01.Y_LaserMark	FG_01

Control implementations

The twin is master for structure, and that is all this page states. Which control function block each instance becomes, its process-image members and its published HMI struct is the control platform's own knowledge base:

• Beckhoff
• Siemens — no knowledge base published yet