Omron CJ1W-DRM21 - Page 198

6 Message Communications
6-10
CJ-series DeviceNet Units Operation Manual for NJ-series CPU Unit(W497)
z 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
Accordingly, set data in the SendCmd instruction as follows.
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/
34 12
Service Data
Eg. For 16#1234
78 56 34 12
Service Data
Eg. For 16#12345678
S+n 34 12
15 08 07 00
Bit
S+n
12
34
15 08 07 00
Bit
Example: 16#1234
Example: 16#12345678
From higher byte From higher byte
From lower byte
S+n
56
12
78
34
15 08 07 00
Bit
From lower byte
S+n 78
34
56
12
15 08 07 00
Bit