Dimensions; Fail-Safe; Relays - Siemens SITRANS L 7ML5400 Operating Instructions Manual

General Operation

7.2 Relays

7.1.1.2

Dimensions

Dimensions of the vessel, wet well, or reservoir (other than low and high calibration points)
are only important if you require volume readings. In this case, all dimensions are used to
calculate the volume value in terms of level. They are also used to calculate pumped volume.
7.1.1.3

Fail-safe

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. (See list of faults that result in
fail-safe in General Fault Codes (Page 273).)
• 2.4.2. LOE Timer LOE Timer (2.4.2.) (Page 179) activates if an error condition is detected.
Upon expiration of the timer, the mA output value and the relay status default to values
based on Material Level (2.4.1.) (Page 179).
• The fail-safe Material Level (2.4.1.) (Page 179) determines the mA output if the LOE Timer
(2.4.2.) (Page 179) expires and the device is still in an error condition.
If fail-safe operation activates frequently, see Diagnosing and Troubleshooting (Page 271).
7.2 Relays
Relays are the primary controls of external devices such as pumps or alarms. The SITRANS
LUT400 comes with extensive control and alarm functions described below.
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Operating Instructions, 04/2021, A5E33329501-AG
SITRANS LUT400