Globals

Global variables are your project's shared memory. ST blocks read and write them to coordinate state across the whole machine — a run flag, a part counter, a setpoint. (For a primer, see the Global Variables tutorial.)

Referencing a global

Address a global with the Global. prefix. Arrays and maps are indexed:

Kind	Form	Example
Scalar	Global.Name	Global.PartCount
Array element	Global.Name[i]	Global.LaneCount[2]
Map value	Global.Name['key']	Global.Setpoints['zoneA']

A mini example

Sum four lane counters into a running total — a FOR loop over an array global:

(* Running total across four lanes *)
Global.Total := 0;
FOR i := 0 TO 3 DO
    Global.Total := Global.Total + Global.LaneCount[i];
END_FOR;

Globals map automatically

When the block runs in a composite, its global references are matched to project globals by name — usually there is nothing to configure. They still appear as global refs on the instance so you can confirm or override them.