Network Meter Block Installation, Operation, & Maintenance Manual
Monitoring and Configuring the NMB 21
• Low flow alarm
• High flow alarm
• Active turbine alarm (available when using the NMB-TMD firmware)
• Active general alarm
• Previous general alarm
• Alarm for wrong setup (available when using the NMB-TMD firmware)
• Alarm for bent blades (available when using the NMB-TMD firmware)
• Alarm for bearing (available when using the NMB-TMD firmware)
4.1.2.2 Digital Inputs
The NMB has two digital inputs (labeled Din1 and Din2). Each input can be configured for one of the
following functions. See Section 4.3.3: Configuring Inputs and Outputs for details about configuring these
digital functions.
• Not configured
• Flow direction
• Seal parameters
• Alarm acknowledgment
4.1.3 Communicating with an MQTT-Protocol Interface
After establishing a network connection for your NMB, you can configure a connection to an MQTT broker.
The message broker can be privately maintained or cloud-based.
An MQTT broker is a third-party application that typically runs on an intranet or cloud-based server that
enables authorized users to subscribe to information from data sources that publish information to the
message broker. By publishing data to a message broker, the NMB enables one or more clients to monitor
or act upon data from the NMB via the MQTT broker.
The NMB publishes data via multiple MQTT topics, which are logically divided into events, process
variables, and configuration data classifications. The process variable and configuration information is
further broken down into categories called data sets. These data sets are also available in both JavaScript
Object Notation (JSON) and Extensible Markup Language (XML) formats for users. The schema
associated with the JSON and XML data sets is also available directly from the NMB.
Topics are either published as they occur (such as events), on a configurable periodic basis (such as every
5 seconds), or only once (such as on power-up or initial connection).
A full list of topics, associated data structures, and process variables available for MQTT can be found in
Appendix A: Data Reference for RESTful and MQTT Schemas.
To use the MQTT interface, you must configure details about the MQTT broker you want to use. For
instructions, see Section 4.3.7.3: Configuring MQTT Server Settings.
4.2 Implementing Security
The NMB provides the following methods for securing configuration settings and data:
• Selecting Seal Parameters for a digital input and wiring the input to an external key switch; when the
input is de-energized, changes to configuration settings are prevented by disabling the tabs in the
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