Transmitting Global-Control Commands - Omron WS02-9094G - V1.0 Operation Manual

Operating the Network
3-6-3

Transmitting Global-Control Commands

Global-Control commands
I/O Data Synchronization
Note
Group Address Setting
Setting the Group
Address of a Slave Device
100
• Mode changes caused by Auto-CLEAR
When the Auto-CLEAR function has been enabled, and one or more of
the slave devices on the network stop I/O data exchange, the Master
Unit's operational mode will automatically change from OPERATE to
CLEAR. This is discussed in section 3-6-4 Using Auto-CLEAR.
• Mode changes caused by PLC mode changes
An operational mode change will take place if the PROFIBUS Master Unit
has been configured to change its operational mode together with the
PLC mode, i.e. OPERATE when the PLC mode is set to RUN/MONITOR
and CLEAR mode, when the PLC mode is changed to PROGRAM mode.
Refer to section 3-4-1 Setting the Master Parameters for more informa-
tion.
The CS1/CJ1W-PRM21 PROFIBUS Master Units support the transmission of
Global-Control commands. These messages are unconfirmed broadcast
messages (i.e. the slave devices do not send a response message), which
can be used to synchronize I/O data related events two more slave devices.
Two types of synchronization can be achieved.
1. Synchronization of input data
The inputs on one or more slave devices are read at the same time. The
synchronized data is transferred to the Master Unit during the next I/O data
exchange cycle. The commands are defined as Freeze and Unfreeze.
2. Synchronization of output data
The outputs on one or more slave devices are set at the same time. The
synchronized data has been transferred to the slave devices during the
previous I/O data exchange cycle. The commands are defined as Sync
and Unsync.
1. The CS1/CJ1W-PRM21 PROFIBUS Master Unit also uses Global-Control
commands to broadcast its own operational mode to other devices on the
network. These Global-Control commands are sent automatically, without
user interference
• to all devices on the network (i.e. not to specific groups),
• always at the start of every I/O data exchange cycle, and
• only when the Master Unit is either in OPERATE or in CLEAR mode
2. The user can only initiate transmission of Freeze/Unfreeze and Sync/Un-
sync to either all slave devices or specific groups of slave devices. These
Global-Control commands are transmitted separately from the automati-
cally transmitted messages, at the end of the PROFIBUS I/O data ex-
change cycle.
User initiated Global-Control commands can be transmitted to either all slave
devices allocated to a Master Unit, or to one or more of up to eight groups of
slave devices. The group addresses are defined by up to eight bits in a group
address byte, which is part of the Global-Control command.
Note If a Global-Control command is targeted to all slave devices, all the group bits
in the group address bytes are set to 0.
In order for a specific slave device to belong to a certain group, the group
assignment for the slave has to be defined through the Generic Slave DTM
Configuration User Interface. A slave device can belong to one or more
Section 3-6