Power reset Radar Level Transmitter

An interviewer asked what will happen to a GWR if you do power reset. What will be the answer?
Your question is little "vague" , as power reset and loss of power supply/loss of signal can be interpreated by different manner.

Is your question refer to loss of power supply of the device?? is that power reset did mnually(hand)?

We do not know also, to which equipment that device is connected, in case of DCS there is surely such Diagnostic Alarm/protection/ watchdog /monitoring .
There is surely in this case a alarm generated on DCS HMI.

The device is studied to achieve a fail safe mode in this case.

You can consider this as a fail safe controls method .

But since the question is not "precise/well formulated", I can not tell you more on it.

Please clarify.

Controls Guy25.
 
A power cycle is power-off, then power-on.

When power is lost any instrument with a 4-20mA current output will output zero current and the receiver device might be programmed to flag/alarm that loss-of-signal externally as an fault state. Receivers typically alarm internally on loss of signal, assuming the power outage does not take down the receiver as well (power for instrumentation was lost at Fukishima nuclear plant until they wired up car batteries to get the instrumentation running).

The level value at the receiver is likely to register as an "off-scale low" condition at 0mA, with the loss of the 4-20mA signal, which could trigger undesireable actions if the power-loss situation has not been addressed in the control strategy, which it isn't in some plants. A low alarm calling for filling action is not particularly desirable when the tank level is not at a low level. But assume power failure has been taken into consideration

On the resumption of power, instruments do not come on-line immediately, they run through an initialization procedure that can take some time, during which the output is fixed and does not reflect the actual process variable. So there's the possibility of level control being done on the wrong level for a short period of time. See an explanation below regarding power-cycling, from a GWR manual.

power-up behavior.JPG
 
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