Ethernet/IP API Connector
Overview
The EtherNet/IP connector provides tag-based read and write access to any EtherNet/IP (CIP) compliant device via implicit I/O assemblies, using the Sres.Net.EEIP SDK. It also supports explicit, on-demand CIP attribute reads/writes via connector methods.
Every poll cycle reads the input assembly instance from the device and updates every subscribed tag from that one buffer, based on each tag's Address (see below). Output writes go through the output assembly instance whenever a tag's value changes.
The connector detects when the underlying session is lost and reconnects automatically without blocking the read cycle - reconnection runs on its own dedicated background thread. Since the EEIP client instance is reused across reconnects rather than recreated, the previous session is explicitly unregistered first (tolerating a failure there, since a session that's already broken is usually why the reconnect is happening in the first place).
Parameters
| Name | Values | Description |
|---|---|---|
| Type | EEIP | The connector type identifier. |
| IP | IP address or hostname | The IP address or hostname of the device. |
| InputAssembly | integer or 0x-prefixed hex | The input assembly instance number to read. |
| OutputAssembly | integer or 0x-prefixed hex | The output assembly instance number to write. |
| UpdateRate | milliseconds (integer) | How often the connector reads the input assembly. Defaults to 1000. |
| ReconnectDelay | milliseconds (integer) | Delay between reconnect attempts while the device is unreachable. Defaults to 5000. |
Supported Tag Types:
| Tag Type | Address | Behaviour |
|---|---|---|
| Bool Tag | byteIndex.bitIndex, e.g. 2.3 | A single bit within the input/output assembly buffer. |
| Any standard tag | A bare byte index, e.g. 4 | A single raw byte. |
| Any standard tag | start-end, e.g. 4-7 | A raw byte range, returned as a byte array. |
| Any standard tag | startasc-end, e.g. 4asc-7 | The literal text asc between two byte indices - reads that byte range as an ASCII string. |
| Any standard tag | byte1,byte2, e.g. 4,5 | Combines two byte indices into a single 16-bit (ushort) value. |
Writable (Out/InOut) tags of any of the above address forms are written back to the output assembly via SetInstance whenever their value changes.
Connector Methods
| Name | Arguments | Description |
|---|---|---|
| WriteData | Class, Instance, Attribute, Value | Writes a single byte value to an explicit CIP attribute, bypassing the assembly buffer. Currently supports digital output boards only. |
| ReadData | Class, Instance, Attribute | Reads a single explicit CIP attribute on demand, bypassing the assembly buffer. |
Addressing
The Address field of a tag follows one of the five formats described above, all relative to the configured input/output assembly buffer. For a one-off read/write against a specific CIP class/instance/attribute rather than the assembly buffer, use RunMethod("READDATA"/"WRITEDATA") instead.