Omron OMNUC W Series Manual page 172

I/O Trace 1 and 2
I/O trace data is stored as shown below. The remainder of the 1,000 points of data (address
#63, bits 8 to 15) is always stored as 0.
15
Address xx
New data
Object 0x68
Instance #3 or #4
Explicit Messages
This section explains the Explicit Message blocks and transfer sequences used for trace data
reading. Trace data reading uses both byte data reading and word data reading, as shown
below.
Reading Byte Data
Command Block
00
1C
Class ID
Service coder
(1C fixed)
Destination
node address
Response Block
Service code
(9C fixed)
Source node
address
Number of bytes received
Note 1. The maximum number of bytes is 200.
2. If the settings for the beginning address and the number of bytes exceed the data capacity (data
traces 1 and 2: 2,000 bytes; I/O traces 1 and 2: 126 bytes), the number of bytes of data to be
read will be returned without generating an error.
Example: If the address is 1000 and the number of bytes is 10, only two bytes of data from
address 1000 will be returned.
13
14
Oldest data
Address #1
Newest data
Address #63
67
Address, Low
Instance ID
9C
Word data, Low
Word data, High
Read data
(200 bytes max.)
6-75
6.9 Tracing Data
1 0
2
Old data
Time flow
Number of bytes to read
Address, High
Word data,Low
Word data, High
6