User manual

6-4 Using Explicit Messaging
Explicit Messages for a PLC or SLC Controller
Transaction blocks in PLC and SLC scanners accommodate both
downloading Explicit Message Requests and uploading Explicit
Message Responses. The scanner module can accommodate one request
or response for each transaction block. Each transaction block must be
formatted as shown in Figure 6.2
or Figure 6.3.
Figure 6.2 PLC Explicit Message Format
Figure 6.3 SLC Explicit Message Format
Refer to Page 6-5 and Page 6-6 for a description of the data that is
required in each word.
Bit 15 0 15 0
Word 0 TXID Command TXID Status
Por t Size Por t Size
Service Address Service Address
Class Service Response Data
Instance
Attribute
Word 6 - 31 Service Data
Word 32 TXID Command TXID Status
Por t Size Por t Size
Service Address Service Address
Class Service Response Data
Instance
Attribute
Word 38 - 63 Service Data
Bit 15 0 15 0
Word 0 TXID Command TXID Status
Por t Size Por t Size
Service Address Service Address
Class Service Response Data
Instance
Attribute
Word 6 - 31 Service Data
Request
Response
Request
Response