78 model 3000 Ethernet Module / DS Connection Module Operation Manual
Chapter 7 Application Interface
7
7.2.3 Transmission line diagnostic frame structure
The transmission line diagnostic frame sent from the EN7 module is as specified below.
Transmission interval: 10 seconds
Protocol: UDP
Destination address: Subnet broadcast
Example: In case of172.16.64.xx, subnet mask: 255.255.192.0
Line A: 172.16.127.255
Line B: 172.16.191.255
Destination port: 48000
Message size: 1036 bytes
Message format
Note: This format does not include the protocal header of UDP, IP, etc.
Note1: EN711, EN731: 0; EN721, EN741: 1
(Do not set other values than the above.)
Note2: <31> to <16>: Reserved <15> to <0>: Sequence Nos. (0 to 1023)
<31> to <16>: Set 0
(Do not set other values than the above.)
Note3: Any data permissible from computers
The EN module sets the IP address of Line A with (Little Endian) and sends it.
Note4: Any data permissible from computers
The EN module sets and sends information on the installed controllers.
The EN modules sends a diagnosis message to each other every 10 seconds for
diagnosis.
Computers can also be added as objects of diagnosis by sending a diagnosis message
using an application. (A dual-line network sends a message of the same content to both
lines A and B every 10 seconds.) Observe the message transmission interval of 10
second. A shorter interval will increase network traffic, while a longer interval may result
in receiving no diagnostic frame.
Each transmission line will be diagnosed normal when data is received from Line A/B.
Thus, whether data is received or not is the basis of judging a transmission line normal or
otherwise. In sending a diagnostic frame, be sure to observe the format mentioned.
offset <31> <0> Remarks
1036bytes
(40CH)
00h Service 0: Single transmission line
1: Dual transmission line
04H InvokeID (Note2)
08H Size 1024 fixed
0CH IP address (Note3) Line A IP address(Little Endian)
10H
.
.
.
408H
data (Note4)
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