Rockwell Automation 1734-APB Point I/O Profibus Adapter Module - Manual (Page 46)

Publication 1734-UM005B-EN-P - June 2001
4-8 Communication and I/O Table Mapping
Get_Configuration
This service permits the master to read out the Identifier bytes for the
actual adapter configuration. (Refer to the previous section for the
format of the identifier byte.)
The table below shows an example of how the identifier bytes from a
Get_configuration response would look like when you have the
following modules in the backplane: slot 1 = 1734-OB4E; slot 2 =
1734-IE2C; slot 3 = 1734-OE2C; and slot 4 = 1734-IA2.
Global_Command
Sync/Freeze
In addition to the cyclic data exchange, which is executed
automatically by the master, the master can send control commands to
a single slave, a group of slaves or all slaves simultaneously. These
control commands are transmitted as multicast commands and permit
use of sync and freeze modes for event-controlled synchronization of
the slaves.
The POINT I/O adapter begins sync mode when it receives a sync
command from the assigned master. The output channels of all I/O
modules are then frozen in their current state. During subsequent user
data transmissions, the output data are stored at the adapter, but the
output states remain unchanged. The stored output data is not sent to
the outputs until the sync command is receivied. Sync mode is
concluded with the unsync command.
Similarly, a freeze control command causes the adapter to assume
freeze mode. In this operating mode, the states of the input channels
of all I/O modules are frozen at the current value. Input data is not
updated again until the master sends the next freeze command.
Freeze is concluded with the unfreeze command.
Identifier Byte Value Description
0 20h 1734-OB4E; 1 byte out, consistency over byte
1 51h 1734-IE2C; 2 words in, consistency over word
2 61h 1734-OE2C; 2 words out, consistency over word
3 10h 1734-IA2; 1 byte in, consistency over byte