ACS712 Help

[BOB_SANTANA]

Hi All
I just need to pick your brain once more .
i am using the ACS712 to measure a current 0-1A and the device is working but i need to know how i can remove the 2.5v offset because when i applied my load the voltage out is only about 2.8V
Is there a way i can remove this offset

http://www.allegromicro.com/en/Products/Part_Numbers/0712/index.asp
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BOB_Santana

[FvM]

By design, the ACS sensors (as other manufacturers current sensors, too) have a bipolar output range with a midscale zero. The most simple way is to substract the offset measurement from result. Alternatively, an analog preprocessing with a differential amplifier could increase the resolution.

But as far as I see from the datasheet, the sensor noise has already a magnitude of several LSB in 10 bit ADC mode without additional gain, thus an additional amplification would be only meaningful with a strong low pass filtering.

[BOB_SANTANA]

Yes thanks for that.
But for my application I am not reading the voltage from the sensor
to the A/D of the Pic.
What I intend to do is to read the current being sent from the sensor but with the sensitivity cranked up ... the output will be "High" (output saturated) with any current being drawn, and "Low" when there's no current.
This way I can then feed it to the PIC via a schmit trigger.
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BOB_Santana

[FvM]

In this case, a comparator with an exactly dimensioned voltage divider for the threshold would be needed.

[Guest]

are there any examples anywhere i can have a look at?

Bob

[Guest]

Anyone know if this can done with the LM311N as I have a few at home.

[BOB_SANTANA]

I am not sure how to use the Balance/strobe pins.
Can you help ?

Regards
Bob
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BOB_Santana