Rockwell Automation 1769-ADN Compact I/O 1769-ADN DeviceNet Adapter - Manual (Page 160)

Publication 1769-UM001B-EN-P - October 2002
B-2 Explicit Messaging Application Examples
Use a “Single Parameter Read” MSG instruction for the Get 1769-ADN
Status message, where one word of status information is read from the
1769-ADN. The user program consists of a single rung containing a
MSG instruction to accomplish the Get 1769-ADN Status.
The following correlates the CIP Generic message terminology with
DeviceNet command terminology and illustrates the values needed
specifically for the Get 1769-ADN Status message:
The following ladder logic program is an example of the MSG logic
needed to initiate an explicit message to the scanner/adapter. This
MSG instruction logic is specifically for the Get 1769-ADN Status
message. Assume the 1756-DNB scanner is in slot 1 and the Logix5550
controller is in slot 0.
Values (Hexadecimal) DeviceNet Terminology CIP Generic Terminology
e Service 1 Service Code
1 Class 2 Object Type
1 Instance 3 Object ID
5 Attribute 4 Object Attribute
1 Service specifies the type of request being delivered. “e” hexadecimal is a “Single Parameter Read”.
2 Class specifies the desired DeviceNet class. “1” hexadecimal is the class code for the identity object.
3 Instance identifies the specific instance within the object class towards which the transaction is directed.
“1” hexadecimal is the instance of the identity object in the 1769-ADN.
4 Attribute identifies the specific characteristics of the object towards which the transaction is directed.
“5” hexadecimal means Status.