ProSoft Technology 5204SE-MNET-PDPMV1 - Manual (Page 178)

5204SE-MNET-PDPMV1 ♦ ProLinx Gateway Reference
Modbus TCP/IP to PROFIBUS DP-V1 Pass-Through Master User Manual
Page 178 of 235
ProSoft Technology, Inc.
December 22, 2009
DFB Acyclic Mailbox Message: Set Slave Mode - Quantum
In addition to station-related user data transfer, which is executed automatically,
the master can send control acyclic messages to a single slave, a group of
slaves, or all slaves simultaneously. These control acyclic messages are
transmitted as multicast acyclic messages. This permits use of sync and freeze
modes for event-controlled synchronization of the slaves.
The slaves begin sync mode when they receive a sync acyclic message from
their assigned master. The outputs of all addressed slaves are then frozen in
their current state. During subsequent user data transmissions, the output data
are stored on the slaves, but the output states remain unchanged. The stored
output data are not sent to the outputs until the next sync acyclic message is
received. Sync mode is concluded with the unsync acyclic message.
Similarly, a freeze control acyclic message causes the addressed slaves to
assume freeze mode. In this operating mode, the states of the inputs are frozen
until the master sends the next freeze acyclic message. Freeze mode is
concluded with the unfreeze acyclic message.
MNETDPV1_MAILVAR_SetSlaveMode Variables - Quantum
This variable structure is the one to use with your control and sequencing logic
when you want to send a request to the PROFIBUS Master to send Sync and
Freeze control messages to a slave or group of slaves.