Backup Of The Real-Time Clock; Retentivity; Parameter Protection - IDEC SMARTRELAY User Manual

4.3.3

Backup of the real-time clock

Because IDEC SmartRelay backs up the internal real-time clock, it continues operation after a
power failure. The surrounding temperature influences the backup time. At a surrounding
temperature of 25°C, the typical backup time of an IDEC SmartRelay is 20 days.
If there is a power outage of an IDEC SmartRelay for more than 20 days, on restarting, the
internal clock is back in the status that it was in before the power outage.
4.3.4

Retentivity

You can set the switching states, counter and time values of many Special functions list - SF
(Page 127) to be retentive. This means that IDEC SmartRelay retains current data values
after a power failure, and that the block resumes operation at the break point. The timer is not
reset, but resumes operation until the time-to-go has expired.
To enable this response, however, the relevant functions must be set retentive. Two options
are available:
R: The data is retentive.
/: Current data is not retentive (default). See the section in topic "Second circuit program
(Page 78)" on enabling and disabling retentivity.
The operating hours counter, seven-day time switch, twelve-month time switch and PI
controller are always retentive.
4.3.5

Parameter protection

In the parameter protection settings, you can determine whether or not you display and edit
the parameters in IDEC SmartRelay parameter assignment mode. Two options are available:
+: The parameter attribute permits read/write access in parameter assignment mode
(default).
-: The parameter settings are read–/write–protected in parameter assignment mode, and you
can only edit them in programming mode. See the parameter protection mode example in the
Second circuit program (Page 78).
Note
Parameter protection covers only the "Set Parameter" window. If you embed variables of
protected special functions in a message text, the variables are still editable from the
message text. To protect these variables, you must also activate the protection of the
message text.
IDEC SmartRelay Manual
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IDEC SmartRelay functions
4.3 Special functions
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