Omron CJ1W-DRM21 Operation Manual page 198

6 Message Communications
Service Data
Word (2-byte) data and double-word (4-byte) data in the Service Data (such as channel data and error
clear codes) shall conform to the command format of specifying the lower byte (L) first, followed by the
higher byte (H). Example) To specify word data 16#1234, specify 16#34 first, and then 16#12. To spec-
ify double-word data 16#12345678, specify 16#78, 16#56, 16#34, and 16#12, in this order.
Command Format Example
Eg. For 16#1234
34
Service Data
Accordingly, set data in the SendCmd instruction as follows.
Example: 16#1234
From higher byte
Bit 15 08 07
S+n 34
From lower byte
Bit 15 08 07
S+n
12
Similarly when word (2-byte) data or double-word (4-byte) data in the Service Data is returned, the
response format is to return the lower byte (L) first, followed by the higher byte (H).
Additional Information
• Since data in the Service Data is stored in the little endien order when used in the response
format, these word (2-byte) data and double-word (4-byte) data must be converted using the
AryBTo instruction. Refer to the NJ-series Instructions Reference Manual (Cat. No. W502.)
• Contact the ODVA to obtain copies of the DeviceNet specification.
ODVA's URL: http://www.odva.org/
6-10
Eg. For 16#12345678
12 78
Example: 16#12345678
From higher byte
00 Bit 15 08 07
S+n 78
12
34
From lower byte
00 Bit 15 08 07
34 S+n
56
12
CJ-series DeviceNet Units Operation Manual for NJ-series CPU Unit(W497)
56 34 12
Service Data
00
56
12
00
78
34