Relay Setting Tool View; Non-Volatile Memory - ABB REX 521 Technical Reference Manual, General

REX 521
4.1.1.3.
4.1.2.
10
Protection Relay
Technical Reference Manual, General

Relay Setting Tool view

To improve usability, a REX 521 specific pull-down menu, View, with three views
has been created to the Relay Setting Tool.
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The Settings view includes the parameters for setting of all the function blocks. The
Configuration view includes signalling and hardware related settings. The
parameters in the Configuration view are advised to be set during commissioning
and service because some of the parameters cause resetting of the device. Please
refer to "Appendix C: Parameters which cause reset" on page 58 for a list of these
parameters. Measured values and registered data, e.g. current, digital input states,
can be uploaded by means of the Measurements & Registered Data view.

Non-volatile memory

The protection relay is equipped with a non-volatile memory for preserving
important data during auxiliary supply breaks. For example, when a setting value is
changed, the new value is stored in the memory at the moment of sending it to the
relay, without additional store commands. The memory does not need batteries, and
a lifelong service is guaranteed.
Following data is stored in the non-volatile memory:
• Setting values
• Display state
• Lockout state
1
• Recorded values
• Last 50 events
When the relay is restarted, the same LED indication and text as before the auxiliary
supply break are restored on the display.
1. Because the storing of the recorded values is a background task, it might be affected
by a sudden auxiliary power failure.
1MRS 751108-MUM