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Chapter 1) 7SR17 Rho Description Of Operation
Fault records are stored in a rolling buffer, with the oldest faults overwritten. The fault storage can be cleared with
the DATA STORAGE>Clear Faults setting.
6.3.5
Demand/Data Log Records
Maximum, minimum and mean values of input currents, voltages and power (where applicable) are available as
instruments which can be read in the relay INSTRUMENTS MENU or via Reydisp.
The Gn Data Log Period setting defines the time between data sampling. Up to 10080 samples are stored.
The Gn Demand Window setting defines the maximum period of time over which the demand values are valid. A
new set of demand values is established after expiry of the set time.
The Gn Demand Window Type can be set to FIXED or PEAK or ROLLING.
When set to FIXED the maximum, minimum and mean values demand statistics are calculated over
fixed Window duration. At the end of each window the internal statistics
are reset and a new window is started.
When set to PEAK the maximum and minimum values since the feature was reset are recorded.
When set to ROLLING the maximum, minimum and mean values demand statistics are calculated over
a moving Window duration. The internal statistics
are updated when the window advances every Updated Period.
The statistics can be reset from the relay fascia, a binary input or communication command. After reset the
update period and window are immediately restarted.
6.3.6
Data Report File
The data report file can be viewed in Reydisp. The report file is triggered automatically on motor start (binary input
or as determined by Rho thermal settings) or on demand (via Reydisp) e.g. to monitor in-service motor running
conditions.
Motor Status
Last Motor Start: Start time, capacity used, maximum current, minimum voltage
49 Thermal Times: To trip, restart allowed/time
Motor Run Times: Current, total, average
Motor Stopped time
Emergency Starts
6.3.7
Disk Activity Warning
The Data Storage facilities offered by the Relay involve archiving large amounts of data to non-volatile memory.
Such functionality is always secondary to the Protection functionality offered by the Relay, this means that data
transfers can take a significant amount of time; perhaps several minutes. If the Relay is power-cycled during a
storage cycle, some of the data will be lost. For this reason, the Relay can provide a visual warning (at the top-
right position of the LCD) that data storage is taking place:
The 'œ' disk symbol shows that the copying of Events, Waveform Records or Fault Records, to non volatile
disk storage, is currently in progress.
Whether this symbol is displayed or not is set by the SYS CONFIG > Disk Activity Symbol setting.
To avoid such data archiving causing a sluggish response of the HMI typically during Testing or Commissioning –
when a considerable number of new Data records are likely to be created – it is possible to temporarily suspend
it. The duration of this block is set by the SYS CONFIG > Archiver Blocking Time setting. Once this Time has
elapsed, the block is removed and all stored data will be archived as usual.
The 'A' symbol at the top-right position of the LCD indicates that new Events, Waveform Records or Fault
Records are currently being held in volatile RAM and the archiving, to non-volatile flash disk storage, is being
temporarily blocked.
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©2014 Siemens Protection Devices Limited
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