Define Subscriber ( aka Client)
The end user of the data. This can range from a high-end ERP management program that tracks information for control and data analytics, to a website that simply displays real-time operational facility data, and anything in between.
A fundamental advantage of MQTT is that data is sent to a central "broker" instead of being directly transmitted to multiple clients such as remote interfaces or management software. The MQTT broker is responsible for maintaining client connections and sending/receiving messages. Client devices, edge gateways, and IT applications (or publishers/subscribers in MQTT language), are freed up to focus on producing and consuming data. This division of labor greatly enhances scalability.
As overall system sizes grow, the CPU resources and bandwidth requirements of the edge gateway remain static. In addition, MQTT is a lightweight protocol. This small footprint means the HMI can be configured as both an edge gateway and an MQTT broker, reducing the need for additional hardware
Content Created by David Franzwa