Use a local variable (front-panel indicator) to communicate between two parallel process loops contained within the same VI, and use a local variable to stop parallel loops with one "stop" button.
Use a global variable to communicate between two parallel process loops contained within different VIs under the same target, and use a global variable to stop parallel loops with one "stop" button.
A single-process shared variable (SPSV) behaves like a global variable that links deterministic and non-deterministic process loops, effectively shielding the deterministic loop from elements that contribute jitter.
Use a functional global variable (FGV) to communicate between two parallel process loops contained within different VIs under the same target, and use a FGV to stop parallel loops with one "stop" button. The "functional" nature of the FGV means that you can create additional functionality beyond that of a basic global variable, e.g., counting and calculations that operate on the stored value.
Use a channel wire to communicate between two (or more) parallel process loops contained within the same VI, and use a channel wire to stop parallel loops with one "stop" button. Requires LabVIEW 2016 or later version.
A quick and easy way for a PC HMI (human-machine interface) VI to observe the state of an RT-hosted network-published shared variable (NPSV) without creating any block diagram code; an alternative to programmatically accessing the NPSV value.
Example of a complete RT system controller based on the Queued Message Handler (QMH) design pattern with multiple parallel task loops implementing behaviors with queued state machines (QSMs), various inter-process communication techniques (queues and local variables), and inter-target communication techniques (network-published shared variables (NPSVs) and network streams). The PC host human-machine interface (HMI) can remotely connect to the system through the network, monitor the status of the security system, and control it remotely.