Micom P721, Technical Manual

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P72x/EN CM/C21 Commissioning and Maintenance
Page 26/28 MiCOM P721/P723
Remove the screws used to fasten the relay to the panel, rack, etc.. These are the screws
with the larger diameter heads that are accessible when the upper and lower flaps are
installed.
Carefully withdraw the relay from the panel or rack because it will be heavy due to the
internal transformers.
To reinstall the repaired or replacement relay, follow the above instructions in reverse,
ensuring that each terminal block is relocated in the correct position and that the case earth
and communication are replaced.
Once reinstallation is complete the relay should be recommissioned.
5.3 Problem solving
5.3.1 Password lost or not accepted
Problem:
Password lost or not accepted
Cause:
MiCOM P721 and P723 relays are supplied with the password set to
AAAA.
This password can be changed by the user (refer OP PARAMETERS menu).
Action:
There is an additional unique recovery password associated with the relay which can be
supplied by the factory or service agent, if given details of its serial number (under the upper
flap of the front panel). With this serial number, contact your Schneider Electric local dealer
or Customer Contact Center (
http://www.schneider-electric.com/CCC ).
5.3.2 Communication
5.3.2.1 Values measured locally and remotely.
Problem:
The measurements noted remotely and locally (via RS485 communication) differ.
Cause:
The values accessible on the front face via the Measurement menu are refreshed every
second. Those fed back via RS485 communication and accessible by the Schneider
Electric’s Setting software generally have skeletal refreshing frequencies. If the refreshing
frequency of the supervision software differs from that of
MiCOM P721 and P723 relays (1s),
there may be a difference between indicated values.
Action:
Adjust the frequency for refreshing the measurements of the supervision software or of the
setting software to 1 second.
5.3.2.2 MiCOM relay no longer responds
Problem:
No response from MiCOM P721 and P723 relays when asked by the supervision software
without any communication fault message.
Cause:
Mainly, this type of problem is linked to an error in the MiCOM P721 and P723
communication parameters.