Explicit Communication

Explicit communication can be used in the EtherNet/IP Device Service. This form of messaging functions as a Client-Server relationship where the Client and Server will send and receive messages asynchronously. This works best for non-real-time messaging where communication is not time critical.

Explicit Device Profile

Explicit communication over EtherNet/IP requires specific attributes to be set within resources in the device profile.

To create a device resource for explicit messaging, the following attributes are required:

Attribute	Description	Valid Values
type	The type identifier telling the device service that this is an EM resource	EM
objClass	CIP object class number	0 to 65536
instID	CIP object instance ID	0 to 65536
attrID	CIP attribute ID (only required depending on service code used)	0 to 65535
serviceCode	CIP service command code	0 to 31

The serviceCode determines whether the attrID attribute is required, as some service code commands are not attribute-specific. The table below lists attribute and data type requirements for the current service codes supported:

Service Code Command	Call Type	Description	Required Attributes	Device Resource Properties
Get Attributes All	Get	Retrieves all attributes for the specified object class and instance ID When invoking this command for the Identity object, the String data type can parse the received data and label each element The Uint8Array data type splits all data in the message into separate bytes	objClass: Any instID: Any serviceCode: 1	Edge Xpert data type: String, Uint8Array readWrite: R
Get Attribute Single	Get	Retrieves a single attribute value	objClass: Any instID: Any attrID: Any serviceCode: 14	Edge Xpert data type: Any readWrite: R
Set Attribute Single	Put	Writes to a single attribute value	objClass: Any instID: Any attrID: Any serviceCode: 16	Edge Xpert data type: Any readWrite: W
Reset	Put	Resets the device Only supported by the identity object class	objClass: 1 instID: 1 serviceCode: 5	UInt8 or Bool readWrite: W
Generic	Get/Put	Using the Uint8Array, any service code can be used	objClass: Any instID: Any attrID: Any serviceCode: Any in the range 0 to 49	Edge Xpert data type: Uint8Array readWrite: As supported by the service code

Explicit Protocol Properties

ExplicitConnected Protocol Properties

The following ExplicitConnected protocol properties are required if an explicit connection type is set to "connected". In order to keep an explicit connection alive, an explicit request will be periodically made to a resource.

Property	Description	Valid Values
DeviceResource	When using explicit communication, a request must be made to the device at a configured interval to keep the connection alive Allows you to choose the device resource from a profile to use as the periodic request	Explicit device resource name that uses the service code of either: Get Attribute Single (0x0E) Get Attribute All (0x01)
SaveValue	Defines whether the received data is pushed to Edge Xpert on each periodic request Set to true to push the received data to Edge Xpert	true false
RPI	The interval at which the periodic request is sent to keep the class 3 connection alive	Interval in milliseconds