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CHAPTER 1: COMMUNICATIONS GUIDE
DNP general
345 TRANSFORMER PROTECTION SYSTEM – COMMUNICATIONS GUIDE
Default variations for Object 1, 2 , 20 , 21 , 22 , 23 , 30 and Object 32 will be set by settings
and returned for the object in a response when no specific variation is specified in a Master
request.
Any change in the state of any binary point causes the generation of an event, and
consequently, if configured, an unsolicited response, or it is returned when the Master asks
for it. The same behaviour will be seen when an analog value changes by more than its
configured deadband limit. There can be up to 3 Masters in total, but only one Serial
Master.
The following Default Classes will be fixed for the different blocks of data:
Binary Input Points Default Class = 1
Analog Input Point Default Class = 2
Counters Default Class = 3
Each Data Point Class can be changed by protocol function code 22 in volatile mode. If a
restart is performed, the new values will be lost.
DNP Object 34 points can be used to change deadband values from the default for each
individual DNP Analog Input point. These new deadbands will be maintained such that in
the case of a relay restart, the values are not lost.
Requests for Object 20 (Binary Counters), Object 21 (Frozen Counters), and Object 22
(Counter Change Events) must be accepted.
Function codes "Immediate Freeze", "Freeze and Clear" etc. are accepted as well.
ETHERNET INTERFACE
1–49
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