ProSoft Technology PTQ-101M - Manual (Page 147)

Reference PTQ-101M ♦ Quantum Platform
IEC 60870-5-101 Master Communication Module
ProSoft Technology, Inc. Page 147 of 181
May 14, 2008
After the initialization procedure is completed, the master and the PTQ-101M
start communicating. If during communication the master fails to respond to a
message from the module, the PTQ-101M will retry for a configured number of
times. If the master still fails to respond, the module will initialize the line again.
7.3.3 Monitor Direction and Control Direction
The protocol specification defines two directions of data: monitor direction and
control direction. These directions are defined by the protocol specification as
follows:
Monitor Direction: The direction of transmission from a slave to the master
Control Direction: The direction of transmission from the master to a slave
Slave Master
Monitor Direction
Control Direction
The points that are typically transferred from the slave to the master are also
known as Monitor Points (or Monitor Information Objects). The points that are
typically transferred from the master to the slave are also known as Control
Points (or Command Information Objects).