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Receiving Explicit Messages Section 9-2
CPU Unit Status Read (Service Code: 40 Hex)
This PLC Object service reads status details (operation status, operating
mode, fatal and non-fatal errors, etc.) from the CPU Unit.
Command Block
Note A body format of either 8 bits or 16 bits is possible.
Response Block
Parameters Service code (command, response): 40 Hex is specified for commands. For
responses, the highest bit will turn ON and C0 Hex will be returned.
Class ID (command): Always C4 (2F).
The class ID depends on the unit version. The class ID is C4 for unit version
2.0 or later, and 2F for unit version 1.0.
Instance ID (command): Always 00 Hex.
Read data (response): The read data is given in the following table. The data
is returned after the service code in the order shown in the table (high to low).
• Operation status: Returns the operation status of the CPU Unit in 1-byte
(2-digit) hexadecimal.
The values of bits 3 to 6 are not fixed. Always mask them when address-
ing the status data.
00
(*)
40
C4
(2F)
(*)
Class ID
Instance ID
Service Code
The class ID depends on the unit version.
Version 2.0 or later: The class ID is C4.
Version 1.0: The class ID is 2F.
C0
Service Code
Detailed status
Operation Status
RUN mode
Fatal error information (L)
Fatal error information (H)
Non-fatal error information (L)
Non-fatal error information (H)
Message exists/does not exist (L)
Message exists/does not exist (H)
Error code (L)
Error code (H)
Error message (16 bytes)
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