Siemens SITRANS LUT400 - Fail-Safe (2.4.)

SITRANS LUT400
Operating Instructions, 07/2019, A5E33329501-AC
175
9.2.4 Fail-Safe (2.4.)
The fail-safe parameters ensure that the devices controlled by the SITRANS LUT400 default
to an appropriate state when a valid level reading is not available. The PV region on LUI will
display dashes (– – – – – – –) until the fail-safe fault has been cleared. (See General Fault
Codes (Page 269) for a list of faults that will cause failsafe.)
Note
When a Loss of Echo occurs
Material Level (2.4.1.) (Page 175
) determines the material level
to be reported when the Fail
-safe timer expires. See Loss of Echo (LOE) (Page 298) for
more detail.
9.2.4.1 Material Level (2.4.1.)
Note
The default is a factory setting and depends whether or not your device was ordered as
NAMUR NE43
-compliant for Fail-safe.
Defines the mA output to use (shown in Current Output Value (2.5.8.) (Page 179)) when the
Failsafe Timer expires and the device is still in an error condition.
Options
HI
20.0 mA (max. mA Limit)
LO
4.0 mA (min. mA Limit)
HOLD
Last valid reading
VALUE User-selected value [defined in Fail-Safe mA Value (2.4.3.)
(Page 175): default 3.58 mA]
Default
VALUE (if ordered with NAMUR NE43 compliant fail-safe preset)
HOLD (if ordered without NAMUR NE43 compliant fail-safe preset)
9.2.4.2 LOE Timer (2.4.2.)
Sets the time to elapse since the last valid reading, before the Fail-safe Material Level is
reported (defined in seconds).
Values
Range: 0 to 7200
Default: 100
9.2.4.3 Fail-Safe mA Value (2.4.3.)
Note
Material Level (2.4.1.)
(Page 175) must be set to
Value
for the Material Level (2.4.1.)
(Pag
e 175) value to be reported.
Allows the user to define the mA value to be reported when the Fail-safe timer expires.
Values
Range: 3.50 to 22.80 mA
Default: 3.58