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Topic: Motor Shield (Read 336 times) previous topic - next topic

Cayenne

How does the current sensor(returned value) translate to a usable value? Current sensing 1.65V/A<--what on earth does this mean?

groundFungus

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How does the current sensor(returned value) translate to a usable value?
The value returned is a usable value if you know how to use it.  Wouldn't be a very useful function if it returned an unusable value.  What is the data type returned?  What do you want to do with the value?   We need to know which library that you are using for a more specific answer.

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Current sensing 1.65V/A<--what on earth does this mean?
Post a data sheet for the sensor.  That may be that the sensor outputs 1.65 volts for each Amp of current through it.

slipstick

What current sensor are you talking about? And what does the question have to do with a motor shield and which motor shield is it?

Steve

MarkT

V/A is volts per amp.  The sensor is outputing a voltage proportional to the sensed current.

Without knowing which motor shield you mean (there are dozens), its hard to say anything else.

(slipstick, good motor shields have current sense so you can implement over-current detection,
stall-detection, and torque control)
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

Cayenne

#4
Jul 28, 2018, 01:22 am Last Edit: Jul 28, 2018, 01:27 am by Cayenne
MarkT hello and thanks.

Well I signed up, and joined this Arduino forum/ sub forum to ask about an arduino motor shield, sorry I thought it was implied. it is an Arduino MotorShield.

"V/A is volts per amp.  The sensor is outputing a voltage proportional to the sensed current." OK makes sense, but 0 to 1024 reading analog pin0 seems arbitrary. I must be looking at the input, or output wrong.

6 volts on the high side of the board drawing ~say~ 250 ma(motor load) looks like what while querying pin A0 Channel A ?

Am I supposed to use some math in the sketch to arrive at a translatable Amp reading?

groundFungus

Analog read voltage

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Am I supposed to use some math in the sketch to arrive at a translatable Amp reading?
Yes.

Cayenne

Sorry all, I failed to RTFM completely!

From the documentation-->"For your convenience it is calibrated to be 3.3V when the channel is delivering its maximum possible current, that is 2A"

Therefore: 0 to 1023 = 0 to 2 Amps

2/1023 = .00195

So analogRead(0) * .00195 = Amps

Disapointing to have such poorly represented hardware on the manufactures website/ forum.

In the future where should I go to get accurate info on arduino products???


Wawa

#7
Jul 29, 2018, 04:55 am Last Edit: Jul 29, 2018, 04:56 am by Wawa
In the future where should I go to get accurate info on arduino products???
Right here.

Somebody would have told you that the current Arduino motor shield (Rev3) is very basic,
with parts dug up from the grave (L298).
Leo..

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