Omron EJ1 - 07-2008, Operation Manual

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Overview of Explicit Message Communications Section 6-1
Data Specifies the details of the commands and set values. The data section is not
required for read commands.
Note The number of digits used for the Class ID, Instance ID, and Attribute ID
depends on the master used. When sending parameters from an OMRON
Master Unit, the values are expressed as follows:
Class ID: 4-digit (2-byte) hexadecimal
Instance ID: 4-digit (2-byte) hexadecimal
Attribute ID: 2-digit (1-byte) hexadecimal
Response Block
• The following format is used when a normal response is returned for the
sent explicit message.
• The following format is used when an error response is returned for the
sent explicit message.
Number of Bytes Received The number of data bytes received from the source node address is returned
in hexadecimal. When an error response is returned for the explicit message,
the contents is always 0004 hex.
Source Node Address The address of the node that sent the response is returned in hexadecimal.
Service Code For normal responses, the value for when the most significant bit (bit 07) of
the service code specified in the command turns ON is returned. (When the
service code of the command is 0E hex, the service code of the response will
be 8E hex.) When an error response is returned for the explicit message, the
contents is always 94 hex.
Data Read data is included only when a read command is executed.
No. of bytes
received
Source node
address
Service code Data
No. of bytes
received
0004 hex, fixed
Source node
address
Service code
Error code
(2 bytes, fixed)