Communicating Using Application Messages

You can communicate with other IzoT devices on a network using an application message. An application message is an unstructured message, unlike a datapoint or property message that is structured based on the datapoint or property type used for the message. Since there is no pre-defined structure for an application message, the sending device and receiving device must use the same definition for the message structure. Application messages are sometimes used to implement private interfaces to an application used for debugging, testing, or manufacturing. To send an application message, create a message tag using the tag class to specify addressing and delivery options for the message.


The following example implements an array of two message tags called tag_a and a single message tag called tag_b.

#include "IzoTDev.h"   

IzotTagtag_a[2]; //@IzoT tag 
IzotTagtag_b;    //@Izot tag bindable(False)

Message tags are bindable by default. This means that message tags correlate to a destination address configurable at runtime and by a network tool to establish communication with other devices. These tags are used to exchange messages between compatible devices, where the connection between the devices is established by a network tool or network integrator.

In the example, the tag_b message tag is declared with the optional bindable attribute set to False (the default is True). A non-bindable message tag consumes fewer system resources, but your application must include all knowledge about the destination device(s) and related protocol properties, such as the service type or appropriate values for related timers.

See IML Syntax Summary for a complete list of modifiers and attributes supported with the tag implementations.