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Topic: Understanding ACS7xx Current Sensor (Read 5 times) previous topic - next topic

retrolefty


retrolefty, your answer scares me.
Look at the pcb, how short the distance is between the current side and the signal side of the sensor. There is even a signal line under the chip.


Yes the PCB trace spacing could be a factor for Pololu warning also, but the trace spacing is the same as the pin spacing of the device and the datasheet certainly doesn't include any voltage limit caution between pins 2 and 3. 

SparkFun sells a 5 amp version of the this chip in a module/breakout form:   https://www.sparkfun.com/products/8882

A couple of users asked if it was suitable for AC power current measurements and other users answered:

Quote

Anyone know if this is suitable for the mains? say 3A max @ 240v AC (UK). I had a quick skim through the datasheet, and didn't seem to find anything :/

Chiel | about 3 years ago  1
the ACS712 is rated to 5A and after searching around on the web for projects using this ic at 220v i would say its usable in europe. the datasheet mentions a Peak Basic isolation voltage of ~380 Volt which could be the maximum voltage the ic can handle. i hope this answers your question.
mattkenny | about 3 years ago  1

I'm using the 20A version of this chip in a device to sense mains current @240V/50Hz (Australia). It handles it just fine.


Of course these are just Internet 'answers' and don't carry any authority.

Lefty

Krodal

retrolefty, a resistor of 1.2mOhm is between pin 2 and 3. So at 30A there is 36 mV between 2 and 3.

retrolefty

#12
Feb 09, 2013, 01:35 am Last Edit: Feb 09, 2013, 01:43 am by retrolefty Reason: 1

retrolefty, a resistor of 1.2mOhm is between pin 2 and 3. So at 30A there is 36 mV between 2 and 3.


So what scares you about the module or my thoughts stated so far? The voltage isolation rating from the datasheet from pins 1-4  and 5-8 pins is stated in the datasheet and would seem to support household AC power usage?

I own a similar +/- 5 amp product from an Asian e-bay seller that I've played around with a little, but only on DC voltages so far.

http://www.ebay.com/itm/5A-ACS712-Module-range-Current-Sensor-Module-/370669739382?pt=LH_DefaultDomain_0&hash=item564da35d76

Lefty

Krodal

retrolefty, look at the pcb, both sides. The copper of the high current (high voltage) side is very close to the sensor signal lines to the Arduino. That's scary. I will work, but not within the safety regulations.

MarkT


retrolefty, a resistor of 1.2mOhm is between pin 2 and 3. So at 30A there is 36 mV between 2 and 3.


Well I would reword that as "the maximum resistance between current terminals is specified as 1.2mOhm" - the resistance
is incidental to the operation of the device since it's a hall-effect sensor - some of that resistance may be the pins, the solder on the
pins, there will be some from the PCB traces too (for 1oz copper board the ohms-per-square is about 0.5mOhm).

Or put another way there will be at least tens of millivolts everywhere at those current levels, and 30A continuous wouldn't be
a sensible application for these sensors.
[ I won't respond to messages, use the forum please ]

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