Go Down

Topic: Measuring voltage external 48VDC PS, without sharing ground (Read 2408 times) previous topic - next topic

MiechH

I have a question regarding the use of an Arduino board to measure voltage of a DC-powersupply without sharing grounds. So there should be a galvanic separation between the circuitry of the Arduino and the 48VDC-powersupply. A friend of mine told me to use the LM321 (Voltage to frequency converter, use the generated pulse-train for Arduino to measure and calculate corresponding voltage) but it can't handle a voltage in excess of 40 VDC. The next problem is, that if the LM321 circuitry uses the same powersupply as the supply it needs to probe, the frequency-value doesn't change when the voltage drops. So how am I going to monitor the output voltage of a 48VDC powersupply with an Arduino, without sharing a common ground? Thanks for your help in advance!

Grumpy_Mike

Use a voltage regulator on the LM321 to run it at lower than the voltage you are trying to measure. Then use a potential divider to feed a fraction of the voltage to measure into the chip. Then couple the output of this chip through a transformer or opto isolator into the arduino.

pito

When the precision is not so important you may simply use an opto-coupler. You have to calibrate it as it is not linear.

pwillard

There are chips designed for dealing with floating power supplies that can provide ISOLATION.

Example:
http://www.ti.com/lit/ds/symlink/iso7240a.pdf

sonnyyu

DC or VARIABLE FREQUENCY VOLTAGE TRANSDUCER

Example

The voltage transducer is pricy, since it has only industrial grade, no consumer grade voltage transducer.



Go Up
 


Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

Arduino
via Egeo 16
Torino, 10131
Italy