Balluff BTL7-T500 Series, Руководство по настройке

Страница: 67 / 82

26 english
4
Configuration (continued)
4.10 The acyclic communication between a
Class-2-Master and a Slave (MSAC_C2)
To be able to access the slave data in acyclic
communication from a Class-2-Master a connection must
first be opened ( Initiate ) and after successful writing and
reading the connection again closed ( Abort ). When the
connection is opened the services Write and Read are also
available.
4.10.1 Telegram Initiate (Initiate.req)
Before a Class-2-Master can begin acyclic data exchange
with a slave, it must use an Initiate.req service via DSAP 49
(to the resource manager) of the slave to specify an
available SAP over which data exchange should take
place. SAPs 0..48 are provided in the slave for this
purpose. The master uses Initiate.req to open the
connection to the slave.
The slave responds with an Initiate.res and uses it to share
the SAP number to be used with the master. The master
must keep the connection open by sending polling
telegrams until it has received the Initiate.res from the
slave. After successful initiation of the connection data can
be exchanged between master and slave. If no data are
exchanged, the master and slave must exchange Idel
telegrams so that the connection can be kept open. The
Idle telegrams are not necessary for Class-1 masters,
since here the connection remains open over the cyclical
channel. To give the slave the possibility of setting itself to
the supported master services, master and slave exchange
the supported services.
The Profile_Ident_Number makes it possible to exchange
manufacturer-specific data structures during data
exchange using the previously described services
DP_Write and DP_Read .
BTL7-T500-…
Configuration Guide