Ignition User Guide

1. Find your broker details

You need four things from whoever runs your Ignition system:

2. Connect the gateway

1. 1
   Open the Connection screen

   The header chip reads Not publishing and the first checklist step, Broker set, is waiting.
2. 2
   Fill in the MQTT broker panel

   Enter the Broker host, the Port if it is not 1883, the Username and the Password. Tick Use TLS only if the broker’s listener uses TLS.
3. 3
   Click Test connection

   The gateway connects to the broker once, without publishing anything, and reports the result under the form. Success reads Connected to <host>. Save to start publishing. A failure says what went wrong; see MQTT broker.
4. 4
   Click Save and connect

   The gateway connects within a few seconds and announces every sensor. The checklist ticks through each step, the last reading Sensors published, and the header chip changes to Publishing to Ignition.

Every whitelisted sensor is published by default, including ones added to the gateway later. To publish only some, turn the others off on the Devices screen.

3. Find the tags in Ignition

1. 1
   Open the Ignition Designer

   The tags live in the MQTT Engine tag provider. Ignition’s gateway web pages show only a tag count per provider, so use the Designer’s Tag Browser to see the tags themselves.
2. 2
   Select the MQTT Engine provider

   In the Tag Browser, switch the provider from default to MQTT Engine.
3. 3
   Open Edge Nodes

   Expand Edge Nodes > NCD > <gateway name>. There is one folder per sensor, named by its radio address. Open Info inside a folder to see which sensor it is.

The checklist

Getting tags into Ignition lists what must be true before tags appear, in order. The first step without a tick is the one to fix.

Below the checklist, the line In Ignition’s Tag Browser, open the MQTT Engine provider shows the exact folder this gateway publishes to.

MQTT broker

Test connection connects once with what is in the form, including unsaved changes, and disconnects without publishing. A blank password tests with the saved one. Failures are reported with advice:

Save and connect stores the form and the gateway reconnects within a few seconds. Saving an empty host disconnects. Moving to a different broker announces the gateway’s departure on the old broker first.

Sparkplug settings

Save settings applies the changes within a few seconds.

Rebirth all tags

Rebirth all tags makes the gateway announce itself and every sensor again, so Ignition rebuilds the tags from scratch with current values. Use it if tags look wrong or incomplete in Ignition. It is the same as the Rebirth command MQTT Engine can send to an edge node, which the gateway also answers.

Folder layout

Edge Nodes/
  NCD/                          Group ID
    Gateway-B00E/               Edge node ID
      Gateway/                  Name, Model, Platform Version, App Version
      Node Status/              Sensors Reporting, Sensors Stale
      Node Control/Rebirth
      0013A20042382D92/         one folder per sensor, its radio address
        Info/                   Name, Location, Asset, Sensor Model, MAC, Sensor Type
        Health/                 Battery Percent, Battery V, RSSI, Counter, Last Seen, Stale
        Sensor                  the readings, a UDT instance (or Data/ in plain folders)

MQTT Engine adds its own Node Info and Device Info folders alongside these, with connection details such as online state and birth and death counts.

Reading names are the metric names Atrium stores, for example x_rms_acc_g, x_velocity_mm_sec or humidity. All readings are 64-bit floating point.

One UDT per sensor type

With the default layout, the gateway defines one data type per sensor model, named NCD_<type>_<model>, for example NCD_114_Standalone_Smart_Vibration_Sensor_v4. MQTT Engine creates these under _types_ in its provider, and each sensor’s Sensor tag is an instance of its type. A template or screen built against the type works for every sensor of that model.

Members carry engineering units where the unit is certain from the reading:

A data type only grows. If a sensor starts sending a reading its type does not have yet, the gateway adds the member and announces itself again, and a member is never removed. Screens bound to a member keep working.

Health and staleness

Health/Stale covers a sensor that goes quiet while the gateway is fine. If the gateway itself drops off the network, the broker publishes its death message about 45 seconds later and MQTT Engine marks every tag from the gateway stale. Both are good candidates for alarms.

Outages and history

Atrium keeps storing readings while the broker or Ignition is unreachable. When the gateway reconnects, it announces each sensor with its newest stored reading, then sends the readings it missed, oldest first, flagged as historical data with their original timestamps, so MQTT Engine does not treat them as the current value.

• Replay reaches back as far as Replay after an outage (hours), 24 hours by default.
• A gateway can take over a minute to notice that its network connection has died. Readings sent in that window may never have arrived, so after an unexpected disconnect the replay also covers the 90 seconds before it. Ignition receives some readings twice; the values and timestamps are identical.
• What MQTT Engine does with historical data is set by Store Historical Events under Connections > MQTT Engine > General Settings, which writes historical change events directly to the history provider instead of updating the tag value.