Step 3: Organize Data

Prerequisite: You should have data flowing from Step 2. If not, go back and complete that first!

Understanding Messages

When data flows through bridges, each message contains:

• payload: The actual data value
• meta: Information about the message (source, destination, tag names, etc.)

In the processing code, you'll work with these as msg.payload and msg.meta.

The Challenge

Right now you have one measurement going to one place:

enterprise.siteA._raw.my_data

But real PLCs have:

• Hundreds of data points with various address formats
• Different data types (numbers, strings, booleans)
• Multiple machines on the same line

Do you need to map each tag manually? No! Let's connect a real PLC and see how automatic mapping works.

Part 1: Connect a Real PLC (Or Simulate One)

Create a New Bridge for a Real PLC

We'll use Siemens S7 as an example, but this works identically with OPC UA, Modbus, or any other protocol.

1. Go to Data Flows → Add Bridge
2. Name: s7-plc
3. Protocol: Select Siemens S7 (or your protocol)
4. Connection:

   • IP: Enter your PLC's IP address (example: 192.168.1.100)
   • Rack: 0
   • Slot: 1

Protocol Selection

Configure What to Read

In the Input section, you'll see protocol-specific settings:

s7comm:
    addresses:
        - DB1.DW20      # Example address
        - DB1.S30.10    # Another address
        - DB3.I270      # Third address
    tcpDevice: '{{ .IP }}'
    rack: 0
    slot: 1

S7 Input Configuration

Automatic Tag Mapping

In the Processing section, look at the Always code:

// Set location from bridge config
msg.meta.location_path = "{{ .location_path }}";

// Use _raw (no validation - data passes through as-is)
msg.meta.data_contract = "_raw";

// Key concept: Protocol address becomes the tag name automatically
msg.meta.tag_name = msg.meta.s7_address;  // For OPC UA: msg.meta.opcua_tag_name

// Pass the value through
msg.payload = msg.payload;

return msg;

Key line: msg.meta.tag_name = msg.meta.s7_address

Each protocol provides its address in metadata:

• Siemens S7: msg.meta.s7_address
• OPC UA: msg.meta.opcua_tag_name
• Modbus: msg.meta.modbus_address

The addresses automatically become tags - no manual mapping needed!

Template Variables

When you entered your PLC's IP address in the Connection settings, it automatically became available as {{ .IP }} in your configuration code. Template variables connect your Connection settings to the processing code:

• {{ .IP }} - The IP address you entered in Connection settings
• {{ .PORT }} - The port you entered in Connection settings
• {{ .location_path }} - The location from Bridge configuration

This makes configurations reusable across different sites - just change the Connection settings and the template variables update automatically.

Learn more: Template Variables Reference

Click Save & Deploy.

See Your PLC Data

In Topic Browser, you now see ALL your PLC data automatically organized:

enterprise.sksk._raw.DB1.DW20     [12345]
enterprise.sksk._raw.DB1.S30.10   ["Product ABC"]
enterprise.sksk._raw.DB3.I270     [789]

(These are S7 addresses, but OPC UA NodeIDs or Modbus registers would appear the same way)

Result: One bridge reads your entire PLC. Every address becomes a tag automatically.

Topic Browser DB1.DW20

Part 2: Special Handling with Conditions

Some PLC tags need special treatment - scaling, unit conversion, or validation. Let's use Conditions to handle specific addresses differently.

Add Your First Condition

1. Below the Always section, click Add Condition
2. If Condition: msg.meta.s7_address == "DB1.DW20" (use the appropriate metadata field for your protocol)
3. Then Action:

// Scale the value and add engineering unit
msg.payload = parseFloat(msg.payload) * 1.0;
msg.meta.unit = "bar";  // This is pressure in bar
return msg;

Add Another Condition for String Data

1. Click Add Condition again
2. If Condition: msg.meta.s7_address == "DB1.S30.10"
3. Then Action:

// Clean up string data
msg.payload = msg.payload.trim();
msg.meta.unit = "Text";  // Mark as text data
return msg;

Processing Conditions

What Conditions Do

• Always section: Runs for EVERY tag (sets basics)
• Conditions: Run ONLY for specific tags (special handling)

You can handle hundreds of tags with just a few conditions for the special cases.

View the Enhanced Data

In Topic Browser, click on DB1.DW20. Notice:

• The value might be scaled
• Metadata now shows unit: "bar"
• Special handling applied ONLY to this tag

Metadata View

Part 3: Organize with Virtual Folders

Right now all tags are at the root level. Let's organize them into logical folders using virtual paths.

Add Organization with Conditions

1. Add Condition for production data
2. If Condition: msg.meta.s7_address.startsWith("DB1")
3. Then Action:

// Group all DB1 data under "production" folder
msg.meta.virtual_path = "production";  // Creates organizational folder
return msg;

1. Add Condition for quality data
2. If Condition: msg.meta.s7_address.startsWith("DB3")
3. Then Action:

// Group all DB3 data under "quality" folder
msg.meta.virtual_path = "quality";  // Creates organizational folder
return msg;

The Result: Organized Folders

In Topic Browser, your data is now organized:

enterprise.sksk._raw.production.DB1.DW20     [12345]
enterprise.sksk._raw.production.DB1.S30.10   ["Product ABC"]
enterprise.sksk._raw.quality.DB3.I270        [789]

• All DB1 tags → production folder
• All DB3 tags → quality folder
• Automatically organized by data block

You organize entire data blocks with one condition, not individual tags.

Part 4: Route to Different Machines

What if different data blocks belong to different machines? Let's route them!

Dynamic Location Routing

Add conditions to route data blocks to different machines:

1. Add Condition for Machine 1
2. If Condition: msg.meta.s7_address.startsWith("DB1")
3. Then Action:

// DB1 belongs to machine-1
msg.meta.location_path = "{{ .location_path }}.machine-1";
msg.meta.virtual_path = "sensors";
return msg;

1. Add Condition for Machine 2
2. If Condition: msg.meta.s7_address.startsWith("DB3")
3. Then Action:

// DB3 belongs to machine-2
msg.meta.location_path = "{{ .location_path }}.machine-2";
msg.meta.virtual_path = "quality";
return msg;

Result

ONE bridge now routes to MULTIPLE machines:

enterprise.sksk.machine-1._raw.sensors.DB1.DW20     [12345]
enterprise.sksk.machine-1._raw.sensors.DB1.S30.10   ["Product ABC"]
enterprise.sksk.machine-2._raw.quality.DB3.I270     [789]

Understanding the Complete Picture

You now control every part of the topic:

umh.v1.enterprise.sksk.machine-1._raw.sensors.DB1.DW20
       └─ fixed ─┘└─ location_path ─┘     └virtual┘└tag┘
                                             path   name

• location_path: WHERE the device is (can be dynamic)
• virtual_path: HOW you organize (folders for grouping)
• tag_name: WHAT you're reading (automatic from S7 address!)

What You've Learned

✅ Protocol addresses become tag names - No manual mapping needed! ✅ Conditions handle special cases - Not every tag, just the exceptions ✅ Folders organize automatically - Group entire data blocks at once ✅ Dynamic routing is simple - Send different PLCs to different locations ✅ Variables make it reusable - {{ .IP }} works for any PLC

Concepts Learned

Building on previous guides, you now understand:

• Template variables - Dynamic configuration using {{ .IP }}, {{ .PORT }}, {{ .location_path }}
• Message structure - msg.meta (metadata) and msg.payload (actual value)
• Conditions - If-then rules in Tag Processor for special handling
• virtual_path - Additional folder organization within topics
• Dynamic routing - One bridge serving multiple locations
• Automatic tag mapping - Protocol addresses become tag names automatically
• Metadata - Additional context in msg.meta (units, sources, custom fields)

What's Next?

You can now:

• Connect entire PLCs with one bridge
• Organize hundreds of tags with a few conditions
• Route to different locations dynamically

But there's still a risk: What if DB1.DW20 suddenly sends a string instead of a number? Or DB3.I270 goes out of range?

Ready to add data validation? → Step 4: Validate Your Data