Rockwell Automation 1771-SDN DeviceNet Scanner Module Installation Instructions - Manual (Page 29)

Publication 1771-IN014B-EN-P - September 2001
DeviceNet Scanner Module Catalog Number 1771-SDN/C 29
The transaction block is divided into two parts:
•
transaction header – contains information that identifies the
transaction to the scanner and processor
•
transaction body – in a request, this contains the DeviceNet
Class, Instance, Attribute and Service Data portion of the
transaction. In a response, this contains only the response
message.
Each of the data attributes in the transaction header are one byte in
length:
•
command/status – for each download, you assign a command
code to instruct the scanner how to administer the request:
For each upload, the status code provides the processor with status on
the device and its response:
Command Code Description
0 Ignore transaction block (block empty)
1 Execute this transaction block
2 Get status of transaction TXID
3 Reset all client/server transactions
4–255 Reserved
Status Code Description
0 Ignore transaction block (block empty)
1 Transaction completed successfully
2 Transaction in progress (not ready)
3 Error – slave not in scan list
4 Error – slave offline
5 Error – DeviceNet port disabled/offline
6 Error – transaction TXID unknown
7 Error – slave not responding to request
8 Error – Invalid command code
9 Error – Scanner out of buffers
10 Error – Other Client/server transaction in
progress
11 Error – could not connect to slave device
12 Error– response data too large for block
13 Error – invalid port
14 Error – invalid size specified
15 Error – connection busy
16-255 Reserved