User`s manual

MGate 4101-MB-PBS UM Quick Configuration
A-5
request telegram for diagnostics or configuration. After its parameters have been set, the slave will proceed
to the I/O Configuration State.
I/O Configuration State
In this state, the slave awaits a configuration telegram that specifies the number of input and output bytes that
are to be exchanged in each data telegram cycle with the slave. The configuration telegram also causes the
slave to check the configuration which was sent against the stored configuration. A slave in this state will accept
a request telegram for diagnostics or configuration, or a set parameters telegram.
Data Exchange State
After parameterization and configuration have been accomplished, the slave cyclically exchanges I/O data with
the master. This is a cyclic transfer of I/O data and possible diagnostic information.
Global_Control Service
ProfiBus DP uses the Global Control function to send special commands addressed to a single slave, a specific
group of slaves (multi-cast), or to all slaves at once (broadcast). ProfiBus sends broadcast and multi-cast
messages as global control telegrams using address 127 (an optional group number is included for a select
group with multi-cast).
Using SDN transmission (Send Data with No acknowledge), a class 1 master will use the Global_Control service
to inform the slaves of his mode (Operating or Clear Mode), or to send commands such as sync, unsync, freeze,
unfreeze, and clear data to a group of slaves, typically for synchronization purposes. Note that a slave will only
accept this command from the same master that parameterized and configured it. There is no response
returned to an SDN telegram.
Sync: The output states transferred in Data_Exchange are delivered and frozen. The output data which follows
is held until the next Sync command or Unsync command.
Unsync: This control cancels the sync command.
Freeze: This causes the states of the inputs to be read and frozen until the next Freeze command or Unfreeze.
Slaves must ensure that following a freeze command, the last frozen values of the inputs must be transferred
in the next data exchange cycle.
Unfreeze: This control cancels the freeze command.
Clear_Data: A class 1 master may use a global control telegram to inform the slaves that it is switching from
Operate Mode to Clear Mode. This bit is set in Clear Mode (0200H), and cleared in Operate Mode (0000H). A
slave will respond by either clearing its outputs, or it may optionally assume a user-defined state with its
master in Clear Mode. Please refer to Failsafe Operation for more information on the use of this bit.