Creating External Tags

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

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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

📷 [Screenshot: 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

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

📷 [Screenshot: OPC UA tag browser showing device hierarchy]

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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)	Line1_Temperature_01
Description	Human-readable label	Oven temperature sensor
Group	Parent group	Temperature_Sensors
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

📷 [Screenshot: 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:
Line1_Oven_Temperature_01
Line2_Motor_Speed_A
Warehouse_Door_Status_North

Organize with Groups

Group tags by:

• Equipment: Oven_Tags, Conveyor_Tags
• Function: Temperature_Sensors, Motor_Controls
• Location: Line1_Tags, Warehouse_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

• Creating Internal Tags: Set up Memory, I/O Mapping, Logic, and System tags
• Configuring Historian: Enable historical data logging for external tags
• Tags Reference: Data types, quality codes, and troubleshooting