working with ACS712 (current sensor)

Status
Not open for further replies.
K

kookooli

Junior Member level 3
Joined
Jul 10, 2014
Messages
30
Helped
0
Reputation
0
Reaction score
0
Trophy points
6
Visit site
Activity points
235
Hi
I'm working with an ACS712 current sensor.
my problem is here:
sensor's output voltage when it is not measuring is not constant.It varies from 2.3 to 2.5.
but it should be fixed 2.5.
what can i do to make that value constant ?
 

The schematics of your application with the sensor will help to look into why the output varies.
 

kookooli said:
My supply voltage is aproximately constant but i dont know why sensor's voltage varies ?
what can I do ?
Click to expand...
Please define: "aproximately constant". Is it 5V +/- 1%, 5%, 10% or what?
An ACS712 output voltage is ratiometric to the input voltage, as described on page 9 of the datasheet:

Ratiometry. The ratiometric feature means that its 0 A output, VIOUT(Q), (nominally equal to VCC/2)

If your output voltage varies without any magnetic fields, then your input voltage must be varying too.
 


Supply voltage is 5.1 volt (5.08 to 5.13 max changes) but sensor's voltage varies from 2.4 to 2.7
what can I do ?
 

Supply voltage is 5.1 volt (5.08 to 5.13 max changes) but sensor's voltage varies from 2.4 to 2.7
Click to expand...
How do you measure it? Are you sure that no current is flowing through sensor?
 

FvM said:
How do you measure it? Are you sure that no current is flowing through sensor?
Click to expand...

I want to measure the output current of a switching power supply via ACS712.
when the switching power supply is not connected to it's supply (220 volt/50 Hz) i measure the sensor's voltage that should be Vcc/2. but it is not and it changes in a spread range from 2.4 to more that 2.7 .
 

If you have no other problems (i.e. solder joints) then you have either a defective device or you have stray magnetic fields affecting the sensor.
 

You didn't answer "How do you measure?". I have to assume that you are using a sufficient accurate measuring method, not a µC ADC, not an oscilloscope that displays wideband sensor noise.
 

hi ,
i'm also trying to get that cip for some industrial application... Do you have a factory made module or you made the circuit yourself? It's clever to check it's power supply . Personally i encountered the problem that i could not calibrate some sensors supplied from a common SMPS power supply (12v/2A) , instead everything worked perfectly when i used 12V lead acid battery ... so it was an EMI issue in the end. Also it's clever to check somehow near by fields since the cip uses Hall sensor as current sensor. You could try to shield that part of the circuit with some steel plate/box.
Ps: does somebody know where to get those modules from EU region ?
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…