GE 845 Instruction Manual page 145

CHAPTER 4: SETPOINTS
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845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
DNP TIME SYNC IIN PERIOD
Range: 1 to 10080 min in steps of 1 min
Default: 1440 min
This setting determines how often the Need Time Internal Indication (IIN) bit is set by the
845 . Changing this time requires the DNP master to send time synchronization
commands more or less often, as this setting time period.
If the requirement for time synchronization is more than a couple of seconds the user is
advised to consider time-sync via other means such as IRIG-B or 1588, given network
asymmetry, the consistency of the network latency, clock drift and additional delays due to
routers located between the client and the 845 , all of which contribute errors.
DNP MESSAGE FRAGMENT SIZE
Range: 30 to 2048 in steps of 1
Default: 240
This setting determines the size (maximum length of frame), in bytes, at which message
fragmentation occurs. Large fragment sizes allow for more efficient throughput; smaller
fragment sizes cause more application layer confirmations to be necessary which can
provide for more robust data transfer over noisy communication channels.
DNP OBJECT 1(2) DEFAULT VARIATION
Range: 1, 2
Default: 2
These settings allow the user to select the DNP default variation number for object types
1, 2, 20, 21, 22, 23, 30, and 32. The default variation refers to the variation response when
variation 0 is requested and/or in class 0, 1, 2, or 3 scans. The DNP binary outputs
typically map one-to-one to IED data points. That is, each DNP binary output controls a
single physical or virtual control point in an IED. In the 845 relay, DNP binary outputs are
mapped to virtual inputs.
DNP OBJECT 20(22) DEFAULT VARIATION
Range: 1, 2, 5, 6
Default: 1
For explanation, see above.
DNP OBJECT 21 DEFAULT VARIATION
Range: 1, 2, 9, 10
Default: 1
For explanation, see above.
DNP OBJECT 23 DEFAULT VARIATION
Range: 1, 2, 5, 6
Default: 2
For explanation, see above.
DNP OBJECT 30 DEFAULT VARIATION
Range: 1, 2, 3, 4, 5
Default: 1
For explanation, see above.
DNP OBJECT 32 DEFAULT VARIATION
Range: 1, 2, 3, 4, 5, 7
Default: 1
For explanation, see above.
DEVICE
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