x/s7Write component: v0.37.0+ Batch writes a list of point values to Siemens S7 series PLCs (S7-200SMART/300/400/1200/1500). A successful write is forwarded via the Success chain.

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

Configuration

Field	Type	Description	Default
server	string	PLC address in host:port format; the ISO-on-TCP default port is 102	127.0.0.1:102
rack	int	Rack number	0
slot	int	CPU slot: S7-1200/1500/200SMART=1, S7-300/400=2	1
timeout	int	Request timeout in seconds	5
points	[]object	Default points table; points supplied via msg.Data take precedence when valid	[]

Point fields

Field	Type	Description	Default
name	string	Point name	None
addr	string	Siemens address (see syntax below); supports ${msg.xx}	None
type	string	Data type, see options below	None
value	string	Value to write (as a string); supports ${msg.xx}	None
scale	float	Optional scale factor; engineering value = raw value × scale + offset	-
offset	float	Optional offset	-
endian	string	Optional byte order	-

Point fields

addr field: Uses Siemens address syntax; supports ${msg.xx} template variables.

• DB area: DB<n>.<DBX|DBB|DBW|DBD><offset>[.bit], e.g. DB1.DBD0, DB1.DBW2, DB1.DBX0.1
• M/I/Q areas: word/dword addresses such as MW0, MD0, IW0, QW0; bit addresses such as M0.1

Data type options:

Type	Bytes	Value format
BOOL	1	Boolean; value accepts true/false/0/1; use a bit address (e.g. DB1.DBX0.1, M0.1); implemented as read-modify-write
BYTE	1	Unsigned byte
INT	2	Signed 16-bit integer
WORD	2	Unsigned 16-bit integer
DINT	4	Signed 32-bit integer
DWORD	4	Unsigned 32-bit integer
REAL	4	32-bit float
LREAL	8	64-bit float
STRING	256	S7 string; content longer than 254 bytes is truncated

Input

Points to write are read from msg.Data (a JSON array); if msg.Data is empty, the configured points are used instead. Each point object has these fields:

Field	Type	Description
name	string	Point name (optional)
addr	string	Siemens address, e.g. DB1.DBD8, M10.5
type	string	Data type
value	string	Value to write; supports ${msg.xx}
scale	float	Scale factor (optional)
offset	float	Offset (optional)

Example msg.Data:

[{"addr":"DB1.DBD8","type":"REAL","value":"23.5"}]

Features

• Periodic writes: Place an endpoint/schedule endpoint before this node to trigger it on a schedule. For on-demand writes, an upstream node may inject the points list via msg.Data.
• Template variables: Point fields such as addr and value support ${msg.xx} / ${metadata.xx} templates.
• Dynamic points precedence: When msg.Data carries a valid points JSON array, it takes precedence; otherwise the configured points are used.
• Chain-scoped connection pool: Other S7 nodes in the same chain may reuse an established TCP connection via ref://nodeID to avoid duplicate connections.
• Failure reconnect/retry: A write failure triggers an automatic reconnect and retry, up to 3 times (maxRetries=3). Any single point failure fails the overall operation and routes to Failure.

Relation Type

• Success: Execution succeeds; the message is sent to the Success chain.
• Failure: Execution fails; the message is sent to the Failure chain.

Example

{
  "ruleChain": {
    "id": "s7_write_demo",
    "name": "S7 write demo",
    "root": true,
    "debugMode": false
  },
  "metadata": {
    "firstNodeIndex": 0,
    "nodes": [
      {
        "type": "x/s7Write",
        "name": "Write PLC data",
        "debugMode": false,
        "configuration": {
          "server": "192.168.1.100:102",
          "rack": 0,
          "slot": 1,
          "timeout": 5,
          "points": [
            {"name":"setTemp","addr":"DB1.DBD0","type":"REAL","value":"${msg.setTemp}"},
            {"name":"start","addr":"M10.5","type":"BOOL","value":"true"}
          ]
        }
      }
    ],
    "connections": []
  }
}