Siemens sitrans LR 400 Instruction Manual page 54

4.3.5: Error Signal (F = 3.6 mA)
Current value of the error signal
Value
In the event of a fault the device applies the current defined here to the analog output.
You can choose between 3.6 mA, 22 mA, 24 mA, Hold 10 s, Hold 1 min, Hold 2 min, Hold 3
min and Hold continuously.
When the Hold... values are selected, the device outputs the last valid value until the set
time has run out or the fault has been eliminated. If the fault persists after the set time
runs out, the analog output switches to an error signal of 3.6 mA.
Note:
A fault is different from a loss of echo which indicates a failsafe condition.
4.4 Digital Output
4.4.1: Function DO (F = Alarm)
Assignment of the digital output
Value
Here you can select whether the digital output supplies the upper or lower limit value of
level or volume or an alarm (device error, measurement error; see Parameter 3. 1 ) to the
control system. If you select the No function option, the digital output is switched off.
Selection of a limit value enables Parameter 4.4.3.
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3.6 mA
22.0 mA
24.0 mA
Hold 10 s
Hold 1 min
Hold 2 min
Hold 3 min
Hold continuously
MaxLim Level
MinLim Level
MaxLim Volume
MinLim Volume
Alarm
No Function
SITRANS LR 400 – INSTRUCTION MANUAL 7ML19985FH03