ProSoft Technology PTQ-101M - Manual (Page 144)

PTQ-101M ♦ Quantum Platform Reference
IEC 60870-5-101 Master Communication Module
Page 144 of 181 ProSoft Technology, Inc.
May 14, 2008
If Maximum ASDU Resp Len = 252:
This example shows that the slave sends all 40 measured scaled points in one
single message, if the message is not greater than 252 bytes. However, some
master devices may not support messages containing this number of bytes. If the
master for a given application supports only 100 bytes, the following
communication procedure would occur: