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current sensor fail condition

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mess123

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Hi, I am working on the design of dc dc converter. I have a input current sensor and I would like to check in the controller program about the health_status of the current sensor. i.e. I want to check in the program whether the input current sensor is good or not. How can I check about whether the current sensor is working or not?
Thanks in advance.
 

keremcant

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you can send a current with a known magnitude and read back the value and compare it with the known value...
 

mtwieg

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What kind of current sensor is it?
 

mess123

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Keremcant, At real time, I won't have any known amount of current in advance to compare with the output of the sensor.

mtwieg, It is to measure current of 250A maximum and gives 5 V output. Can be biased to provide negative and positive current reading.

---------- Post added at 02:55 ---------- Previous post was at 02:49 ----------

its a halleffect sensor
 

mtwieg

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With a hall effect sensor one of your main failure modes will be core magnetization, which will happen if it's heavily overloaded for some amount of time. This will result in the current measurement having a DC bias. The only ways to detect this are to either have a reference current to check against (as keremcant suggested) or another transducer (of a more robust type) to compare with the first.

Having a reference current may be feasible. If the current you're measuring is AC, then you can run a 1A dc bias winding through the sensor (with many turns to boost the output), then use the DC bias read on the output as a health check.
 

mess123

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What is the rough time period before it fails due to core magnetization??
 

mtwieg

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It doesn't really take any certain amount of time. All that's required is that the core field strength surpasses some point and you get field remenance.

Remenance and magnetization are also more likely to happen if current flows while the supplies for the transducer are off (in the case of closed loop transducers, that is).
 

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