Viewing Real-time Values
This guide explains how to monitor the current values of registered PLCs and tags in real-time. The gateway provides three types of live views.
| View | Polling Interval | Purpose |
|---|---|---|
/ui/connect/list (Left OPC + Right Tag Table) | 5 seconds | All tag values of a single OPC at a glance |
/ui/connect/tag-view/{opc_id}/{tag_id} (Single Tag Live Chart) | 1 second | Trend and time series of a specific tag |
/ui/main Card | 1 second | Gateway system status (CPU/Memory/Network/Sparkplug, etc.) |
1. Viewing from the [Connection List] Screen (/ui/connect/list)
This is the simplest method.
- Click the Connection List icon in the top bar or the Connection List (N) home card.
- Click the desired PLC row in the [OPC List] on the left.
- The tag list and current values for that PLC will appear on the right.
- Data refreshes automatically every 5 seconds.
For detailed columns and actions, refer to the Connection List / Tag List Screen.
2. Single Tag Live Chart (/ui/connect/tag-view/{opc_id}/{tag_id})
To perform a detailed analysis of a specific tag's time series, click the tag row to move to the separate tag-view page (or enter the URL directly).
2.1 Screen Layout
┌────────────────────────────────────────────────────────────┐
│ ⊙ {OPC_ID} / {TAG_ID} [←] [↻] │
├────────────────────────────────────────────────────────────┤
│ [태그 메타 패널] │
│ tag_id / java_type / plc_address / opc_id / 마지막 갱신 │
├────────────────────────────────────────────────────────────┤
│ [값 추이 차트] [범위 콤보 ▼] │
│ ┌──────────────────────────────────────────────────────┐ │
│ │ (수치/불리언 — ECharts 라인 / STRING — vis 박스) │ │
│ │ │ │
│ │ [── dataZoom 슬라이더 (연한 그레이) ────────] │ │
│ └──────────────────────────────────────────────────────┘ │
└────────────────────────────────────────────────────────────┘
2.2 Chart Types (Automatic Branching)
| Data Type | Chart |
|---|---|
Integer / Long / Float / Double | ECharts Line — Smooth spline + right Y-axis |
Boolean | ECharts step end — 0/1 step type |
String | vis-timeline Box — Groups continuous identical values into one box (State machine visualization) |
2.3 Chart Interaction
| Feature | Description |
|---|---|
| Range Combo | 1분 / 5분 / 10분 / 30분 / 1시간(default) / 3시간 / 12시간 / 24시간 — Immediate re-fetch from Cassandra tm_tag_point upon selection |
| dataZoom Slider | Horizontal bar at the bottom — Drag to zoom/pan horizontally. Light grey tone (updated from previous dark color) — Does not obscure the chart body |
| Auto-addition | 1-second polling pushes new values to the chart (incremental addition without full redraw) |
| Mouse Hover | Tooltip displays value with millisecond precision |
| STRING Chart Update | Reconstructs the entire vis dataset after ASC sorting of history — No flickering for continuous identical values |
Uses the same tone and data as the right-side chart in the OPC UA Server — however, tag-view is full-screen for a single tag, while the OPC UA viewer uses a tree + small chart panel.
3. Table Columns (Reference)
Left [OPC List]
| Column | Meaning |
|---|---|
| PLC | Protocol | Logo and type per protocol |
| Connection Status | 🟢 Connected / 🔴 Disconnected / ⬜ Unknown |
| OPC ID / Name / Description | Identification / User label |
| Collection Interval (ms) | timecycle |
| Auto Start / Asynchronous | Option ✓ / - |
| Connected Tag Count | Number of tags for that OPC |
| Collection Count | Cumulative read count since boot (point_count) |
| Collection Status | 🟢 Normal / 🟧 Anomaly / ⬜ Stopped |
| Action | ▶ Start / ⏹ Stop / 🔧 Edit / 🗑 Delete |
(For the full 14-column original, see Connection List)
Right [Tag List]
| Column | Meaning |
|---|---|
| TAG ID / Name | Identification / User label |
| PLC Address | Reading location (e.g., D0, M10, 40001) |
| Data Type | INT / DOUBLE / BOOL / STRING ... |
| Last Value | Most recent collection (round solid badge — pp-cell-pill tone. Column width 160px) |
| Update Time | Last refresh timestamp |
| Read Status | OK (green solid) / ERROR (red solid) |
| Read Error Message | Reason for failure (empty on success) |
| Action | ✏ Inline Write / 📈 Chart (moves to tag-view) |
Overview from the Main Screen
Return to [Home] (or click the top-left logo) to see the overall gateway status on one screen.
| Display Area | Information Provided |
|---|---|
| CPU / Memory / Disk Gauges | Gateway PC resource status |
| Connection / Tag Count | Summary of total registered counts |
| PLC Connection and Collection Status | Count of normal/failed connections, cumulative collection count |
| Processing Speed (mps) | Trend graph of processed cases per second |
If a gauge turns red, it indicates insufficient resources. Please contact the system administrator.
For Motor Sense
Connections of type MOTOR_SENSE are displayed as Asset Cards instead of the standard tag table.
- HEALTH INDEX Card — Asset health index (Imbalance / Alignment / Bearing, etc.)
- SIGNAL Card — Signal values such as vibration / temperature / voltage
These are automatically updated every 1 second without a separate refresh indicator.
Fetching Values from External Systems
If another system (dashboard, analysis tool, etc.) needs to receive values from the gateway, you can choose from the following methods:
| Method | Who uses this? |
|---|---|
| MQTT Subscription | General IIoT systems |
| Sparkplug B Subscription | Ignition / HiveMQ Edge / Standard SCADA |
| REST API Query | Custom-developed dashboards / back-ends |
| Exposure as OPC-UA Server | External SCADA connecting as an OPC-UA client |
Detailed configuration, topics, and endpoint specifications are available in Advanced — REST API / Advanced — Sparkplug B.
FAQ
Q. Values are coming in, but the update is too slow.
The collection interval may have been set too long during tag registration. Try reducing 수집 주기 (ms) in the PLC registration [Edit] menu. Typically, 1000ms (= 1 second) is standard.
Q. The 5-second screen refresh is too slow.
The table refresh for /ui/connect/list is 5 seconds. To monitor a single tag more quickly, click the tag to move to the Single Tag Live Chart (/ui/connect/tag-view) — which uses 1-second polling. To view multiple tags quickly and simultaneously, use a separate dashboard tool (such as Grafana). Refer to Application Management.
Q. Some tags from the same PLC are normal, while others show errors.
If only specific tags are failing, it is usually because the PLC address notation is incorrect or the format auxiliary (format) does not match. Please re-examine those specific lines using the [Edit] function.