IEC-60870-5-104 (104S) Protocol Implementation
104S
♦
ProLinx Gateway
Protocol Manual
(Firmware v3.00 and later)
Page 102 of 157
ProSoft Technology, Inc.
January 22, 2010
Example - Event Priority
If the gateway is configured with the example values above, and the event queue
contains the events generated in the following order:
Event Order
ASDU
1 M_SP_NA
2 M_SP_NA
3 M_DP_NA
4 M_ST_NA
5 M_DP_NA
6 M_SP_NA
The gateway will respond to a class one data request from the controlling station by
returning the data in the event queue in the order shown in the following table.
Packet Order
Content
1
M_ST_NA event 4
2
M_DP_NA events 3 and 5
3
M_SP_NA events 1,2, and 6
Note:
Events are packed into messages in order to maximize the efficiency of the network and only a
certain number of events can be sent in any one message packet. Therefore, the following cautionary
information must be considered when deciding whether or not to use
Event Priorities
. If this feature is
enabled, events from the highest priority queues are always reported, when present, before events
from the lower priority queues. This means that, if a high volume of high-priority events happens,
events in the lower priority queues may be lost due to low-priority event buffers filling up and
overflowing.
If this feature is not utilized, each ASDU's events are stored in their own queue. The gateway will report
each queue containing events in a round-robin fashion with all the data for each ASDU being packed.
This methodology lowers the possibility of a buffer overflowing and still maximizes the use of bandwidth
on the communication channel.
Summary of Contents for ProLinx 104S
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