Sharp Z-336J - Manual (Page 96)

9-19
Chapter 9: Message transfers
9
[2] Basic format of computer link commands
(1) Communication format
When a computer link is used, data sent from this node to a target node is referred to as a [com-
mand], and data received from the target node by this node is referred to as a [response]. The
communication format for commands and responses is as follows.
Header : Normally, all 40 bytes are 00
(H)
.
If you want to communicate with Ethernet over two layers, you have to use an exten-
sion header.
(See "[5] Two-layer communication with Ethernet")
c-ID : 47
(H)
r-ID : 45
(H)
ATTR : 00
(H)
COM : Command code (See page 9-14)
RSLT : Command execution result
Normally terminated with 00
(H)
If any byte other than 00
(H)
is found, an error code will be output (See "[4] Computer
link error code table").
If an error code is output, there is no response text.
Command Text : Command details (See "[3] Descriptions of each command")
Response Text : Response details (See "[3] Descriptions of each command")
[Example] When you want to monitor the ON/OFF status of relay 04033 See page 9-17.
Remarks
The maximum data length for read/write operations is 1024 bytes. In case of two-layer communication
with the Ethernet, however, the maximum length is 256 bytes. For the UDP, the total number of bytes
from the header to the command text must be less than 1024 bytes.
Ë Command
Ë Response
c-ID ATTR COM
Command Text
r-ID ATTR COM RSLT Response Text
ON
00 00 00 00 03 01 03 20 47
00 00 00 00 00 03 01 03 01 20 45
Header (40 bytes)
Header (40 bytes)
File address
000403 (8) = 0103 (H)
File address
000403 (8) = 0103 (H)
File 0
File 0
Bit 3
Bit 3
Relay No. 04033
Relay No. 04033
Ë Command
Ë Response
Header (40 bytes)
Header (40 bytes) c-ID
r-ID
ATTR
ATTR
COM
COM
Command Text
Response Text RSLT
+2000 +2047 +2050 +2051 +2052 +2053
+0000 +0047 +0050 +0051 +0052 +0053 +0054