x/eipWrite component: v0.37.0+ Writes tag values in batch to Rockwell Automation Allen-Bradley ControlLogix/CompactLogix/Micro820 PLCs over the EtherNet/IP (CIP) protocol. Only CIP devices are supported; PCCC protocol devices such as PLC5, SLC, and MicroLogix are not supported.

Additional extension library required: rulego-components-iot (opens new window)

Configuration

Field	Type	Description	Default
server	string	PLC host address (host only); port 44818 is built in by gologix, e.g. 127.0.0.1; supports ref://nodeId to reuse an existing connection in the chain	127.0.0.1
slot	int	CPU slot on the backplane; auto-generates the CIP path (e.g. 1,0)	0
path	string	Optional CIP path override, e.g. 1,0; empty = auto-generated from slot	None
timeout	int	Request timeout in seconds	5
points	array	Default points table; points in msg.Data take precedence	None

Points fields:

Field	Type	Description
name	string	Point name
addr	string	Controller tag name (CIP tag), e.g. MyTag, MyDB.Temperature
type	string	Tag data type, required (gologix Write needs an explicit type to encode the value); see options below
value	string	Value to write (as a string); supports ${msg.xx} template variables
scale	float	Optional scale multiplier (default 1); conversion formula eng = raw*scale + offset
offset	float	Optional offset (default 0)

Point Fields

addr: Controller tag name. Supports controller-scoped tags (e.g. Temperature), struct members (e.g. MyDB.Temperature), array elements (e.g. MyArray[0]), and program-scoped tags (e.g. Program:MainProgram.Tag).

type: Tag data type, required. gologix Write needs an explicit type pointer to encode the value correctly; it cannot be inferred automatically.

Supported values (case-insensitive):

Category	Accepted aliases
Boolean	BOOL (value accepts true/false/0/1)
8-bit integer	BYTE, SINT, USINT
16-bit integer	INT, INT16, UINT, WORD, UINT16
32-bit integer	DINT, INT32, UDINT, DWORD, UINT32
64-bit integer	LINT, INT64, ULINT, UINT64
32-bit float	REAL, FLOAT
64-bit float	LREAL, DOUBLE
String	STRING

value: The value to write, in string form. Integers accept decimal and 0x hexadecimal prefixes; booleans accept true/false/0/1; floats are parsed by Go's standard rules.

Input

The list of points to write is read from msg.Data in the format below; when non-empty it takes precedence over the configured points:

[
  {"addr": "MyDB.Setpoint", "type": "REAL", "value": "50.5"},
  {"addr": "MyDB.Running", "type": "BOOL", "value": "true"},
  {"addr": "MyDB.Count", "type": "DINT", "value": "${msg.counter}"}
]

value supports ${msg.xx} / ${metadata.xx} template variables, making it easy to write dynamically based on upstream messages.

Features

1. Periodic writes: Pair with an endpoint/schedule endpoint upstream as a trigger; maintain points in the points configuration.
2. Template variables: Point fields (name/addr/type/value) support ${msg.xx} / ${metadata.xx} placeholders.
3. Dynamic points: Points in msg.Data take precedence over configured points.
4. Same-chain connection pool: Other nodes in the same chain can borrow the EtherNet/IP connection already established by this node via ref://nodeId, avoiding duplicate connections.
5. Auto-reconnect & retry: On write failure the node reconnects and retries automatically, up to 3 times.

Relation Type

• Success: On successful execution, the message is sent to the Success chain.
• Failure: On failed execution, the message is sent to the Failure chain.

Execution Result

Does not change the message payload.

Example

{
  "ruleChain": {
    "name": "eip-write-demo",
    "root": true,
    "debugMode": false
  },
  "metadata": {
    "endpoints": [],
    "nodes": [
      {
        "type": "x/eipWrite",
        "name": "write tags",
        "debugMode": false,
        "configuration": {
          "server": "192.168.1.10",
          "slot": 0,
          "timeout": 5,
          "points": [
            {"name": "setpoint", "addr": "MyDB.Setpoint", "type": "REAL", "value": "50.5"},
            {"name": "running", "addr": "MyDB.Running", "type": "BOOL", "value": "true"}
          ]
        }
      }
    ],
    "connections": []
  }
}