The format for a compound message in a transmission area is:
Description |
Size (in bytes) |
|
Format |
2 |
|
Reserved |
2 |
|
Number of Sub-Packets |
2 |
|
|
Sub-Packet 1 Domain |
2 |
|
Sub-Packet 1 Domain Offset |
2 |
|
Sub-Packet 1 Length |
2 |
|
Sub-Packet 1 Timestamp |
8 |
|
Sub-Packet 1 - first data word |
|
|
. |
|
|
. |
|
|
Sub-Packet 1 - last data word |
|
|
. |
|
|
. |
|
|
Sub-Packet n Domain |
2 |
|
Sub-Packet n Domain Offset |
2 |
|
Sub-Packet n Length |
2 |
|
Sub-Packet n Timestamp |
8 |
|
Sub-Packet n - first data word |
|
|
. |
|
|
. |
|
|
Sub-Packet n - last data word |
|
Where:
Format must be 1.
Number of Sub-Packets is the number of Simple Messages contained in the Compound Message.
Each sub-packet is essentially a Simple Message that has a common header and a variable length data area. The sub-packet header is as follows:
Sub-Packet Domain - the PLC data type from which the data in the Sub-Packet originates. The contents of this field will be a number representing the data type as follows:
Value |
PLC Data Type |
0 |
Local Data Block (%L) 90/70 Only |
8 |
Register table (%R) |
10 |
Analog Input table (%AI) |
12 |
Analog Output table (%AQ) |
16 |
Discrete Input table (%I) |
18 |
Discrete Output table (%Q) |
20 |
Discrete Temporary (%T) |
22 |
Discrete Internal (%M) |
56 |
Genius Seamless (%G) |
24 |
Special Contacts A (%SA) |
26 |
Special Contacts B (%SB) |
28 |
Special Contacts C (%SC) |
30 |
System Fault , (%S) read only |
Sub-Packet Domain Offset - the domain start address of the data in the Sub-Packet. This field is numeric and quoted in units of the domain data type starting at zero.
Sub-Packet Length - the length of data in the Sub-Packet. This field is numeric and quoted in bytes.
If the Sub-Packet domain is %L, then the first 8 bytes of data contain the block name for the %L domain.
Timestamp -the time relating to the data in the Sub-Packet, in CIMPLICITY COR_STAMP format.