Micom P721, Technical Manual

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Communication database P72x/EN CT/A11
MiCOM P721/P723 Page 53/78
5.9 Cyclic measurements
The relay will produce measured values using ASDU 9 and ASDU 3.4 on a cyclical basis,
this can be read from the relay using a Class 2 poll.
It should be noted that the measurands transmitted by the relay are sent as a proportion of
2.4 times the rated value of the analogue value. The selection of either 1.2 or 2.4 for a
particular value is indicated in APPENDIX 1.
5.10 Commands
A list of the supported commands is contained in APPENDIX 1. The relay will respond to
other commands with an ASDU 1, with a cause of transmission (COT) of negative
acknowledgement of a command.
I
f the relay takes in account the command, it will answer
with an ASDU 1, with a cause of transmission (COT) of positive acknowledgement.
A blocking command (Control directioncan be introduced using a communication parameter.
5.11 Disturbance records
The disturbance records stored by the relay cannot be extracted using the mechanism
defined in the IEC60870-5-103 standard.
A list of the analog channels and tags (logic
signals) for record extraction is indicated in APPENDIX 1.
5.12 Blocking of monitor direction
The relay does not support a facility to block messages in the Monitor direction.IEC 60870-5-
103 DATABASES