Creating External Tags

This guide shows you how to create external tags that communicate with PLCs, sensors, and other industrial devices.

When to Use This Page

Use this page when:

• you already have a real controller or device
• you know the protocol and at least a few test addresses
• you want to keep an external-channel structure even before hardware arrives

If you have no hardware and only want the fastest learning path, start with Creating Internal Tags first.

Before You Start

Make sure:

• a project is already open in Editor
• you know the protocol, IP address, and basic address format
• you have one small test set of tags instead of importing everything at once

Expected Result

After this page, you should have:

• one external communication channel
• one group under that channel
• three verified starter tags
• a successful check in Start Debug

Note: Depending on the build, the main creation action may appear as Add or New. Use the action that opens the channel or tag creation dialog in your project.

Day-1 Quick Path

For the first success milestone, keep the path short:

1. create one channel
2. create one group
3. manually add three starter tags
4. save and optimize
5. verify values in Start Debug

If your protocol supports browsing or bulk import, you can still use it later. It is usually better to validate a few manual tags first.

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Step 1: Create a Communication Channel

1. Navigate to External Channels tab
2. Click Add → External Device
3. Select the protocol (e.g., Modbus TCP, Siemens S7, OPC UA)
4. Enter channel name
5. Configure connection parameters

Example: Modbus TCP Configuration

📷 [UG-TAGS-EXT-01] Modbus TCP channel configuration dialog

Parameter	Description	Example
Device IP	IP address of the PLC/device	192.168.1.100
Device ID	Modbus slave ID	1
Port	TCP port number	502 (default)
Timeout	Communication timeout	3000 ms
Base Address	Address offset (0 or 1)	1 (default)

Advanced Settings:

Parameter	Description	Default
Byte Order	Endianness for 32/64-bit values	2143 (CDAB)
Independent Link	Dedicated TCP connection	Disabled
PDU Diagnostics	Protocol validation	Enabled
PDU Length	Max bytes per request	220
PDU Immediate Submit	Skip batching for faster response	Disabled
Static Simulation	Test mode without real device	Disabled

💡 Tip: Enable Static Simulation during development to test views without connecting to physical devices.

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Step 2: Create Groups

Organize tags into logical groups:

1. Select the channel
2. Click Add Group
3. Enter a group name (e.g., Temperature_Sensors, Motor_Controls)
4. Click Confirm

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Step 3: Add External Tags

Method 1: Manual Creation

1. Select a group
2. Click Add in the toolbar
3. Configure tag properties in the list

Method 2: Load from Device (Advanced)

Some protocols (OPC UA, S7Comm Plus, EtherNet/IP) support browsing device tags:

1. Select a group
2. Click Load Tags
3. Browse the device tag tree
4. Select tags to import
5. Click Add

📷 [UG-TAGS-EXT-02] OPC UA tag browser showing device hierarchy

Recommended First External Tag Set

For the first external-tag test, keep the scope small:

Tag Name	Type	Example Address	Why start with it
Temperature	Float32	400001	Easy analog value to display on a screen
Pressure	Float32	400003	Second analog value for comparison and trends
MotorRunning	Bool	300001	Simple status bit for indicators and alarms

If you are using Static Simulation, use the same tag set so the rest of the guides still match your project.

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Step 4: Configure Tag Properties

Property	Description	Example
Tag Name	Unique identifier (letters, numbers, underscore, dot; must start with letter/underscore)	Temperature
Description	Human-readable label	Main process temperature
Group	Parent group	Process_Values
Data Type	Value type	Float32, Int16, Bool, String
Address	Device register address	400001 (Modbus holding register)
Access Mode	Read/write permissions	Read/Write, Read Only, Write Only
Poll Interval	Update frequency	100ms, 500ms, 1s
Poll Mode	When to collect data	Service Running, Page Usage
Scale Factor	Multiply raw value	10 (display 100 for raw value 10)
Decimal Places	Precision	2 (show 12.34)
Rounding Rule	How to round	Round, Truncate, Ceiling
Historian	Enable historical logging	Enabled / Disabled

Modbus TCP Address Format

Register Type	Address Range	Bit Address	Data Types	Access
Coil Status	000001-065536	N/A	Bool	Read/Write
Discrete Input	100001-165536	N/A	Bool	Read Only
Input Register	300001-365536	0-15	Bool, Int, Float, String	Read Only
Holding Register	400001-465536	0-15	Bool, Int, Float, String	Read/Write

⚠️ Caution: Address formats vary by protocol. Refer to the "Device Communication Manual" for protocol-specific details.

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Step 5: Optimize Tag Configuration

Click Save and Optimize to validate your tag configuration:

Validation Checks:

• Address Overlap: Detects tags with overlapping memory addresses (writing one tag may change another)
• PDU Length: Ensures tag size doesn't exceed the PDU limit

📷 [UG-TAGS-EXT-03] Optimization results showing warnings with hover tooltips

Hover over warning icons to see details. Fix issues or click Ignore to dismiss warnings.

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Step 6: Test Communication

1. Click Start Debug in the toolbar
2. Monitor tag values in real-time
3. Write test values to writable tags
4. Check quality status codes

Quality Status Codes:

Code	Description	Action
0	Success	Normal operation
1	Tag name not found	Verify tag exists
2	Data type mismatch	Check data type compatibility
3	Device disconnected	Troubleshoot network/device
4	Other error	Check logs for details

Debug Columns:

• Current Value: Live tag value (editable for write operations)
• Quality: Status code (see table above)
• Last Change: Timestamp of last value change
• Poll Status: true (actively polling) or false (not polling)

💡 Tip: Use Poll Mode = Page Usage for HMI applications to reduce CPU load. Tags only poll when displayed on an active view.

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Best Practices

Naming Conventions

Use consistent, descriptive names:

<Line>_<Equipment>_<Parameter>_<Index>

Examples:
Station_A_Temperature_01
Station_A_Pressure_01
Station_A_MotorRunning

Organize with Groups

Group tags by:

• Equipment: Pump_Tags, Motor_Tags
• Function: Temperature_Sensors, Motor_Controls
• Location: Station_A_Tags, UtilityRoom_Tags

Optimize Poll Intervals

Update Frequency	Poll Interval	Use Case
Critical control	100ms	Safety interlocks, fast loops
Real-time monitoring	500ms - 1s	HMI displays, alarms
Slow processes	5s - 1m	Temperature, batch status
Status checks	1m+	Equipment health, diagnostics

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Next Steps

• Understanding Views: Move on after your tags show healthy values or successful simulation behavior
• Creating Monitoring Views: Bind the verified tags to your first runtime screen
• Configuring Historian: Add history after the first monitoring path is working
• Tags Reference: Return here for data types, quality codes, and troubleshooting