Need help on 8 current sensor signal to RS232 signal to read by controller

Thread Starter

Rameshkumar T

Joined Nov 5, 2018
Hello EE,
I am using 8 current sensor to measure 208V AC current of each 8 line. I have only two digital input pin to read all the eight signal.
current sensor 1:1000 ratio for 10A.
I have converted current sensor to voltage level of 5V circuit.
All the 8 sensor voltage signals need to be converted to serial input signal(RS232) to my controlller to read.

What is the circuit can i use?
What is the basic requirement ?
Please provide me some circuit or digital conversion methods.

Thanks in Advance


Joined Jun 19, 2012
Depending on the speed and resolution required...

Is the current signal AC?

Use a micro-controller with 8 analog inputs to it's on-board ADC. Scan the 8 channels, digitize.
Maybe you can synchronize the data sampling to the AC line, to sample each current at the peak.
-or- use a precision rectifier circuit to make the value into a DC signal and sample that.

Format the data into a packet of serial data, with a unique framing character so you can unravel it easily on the receiving end.


Joined Mar 10, 2018
Something like this. Shown is low end part. All components onchip. Note
other resources are available, not used, see resource window on right.
A component list attached. low end part is subset. High end low cost
board is $ 10, other facilities like digital filter, DMA, more analog, digital....

A component is an onchip resource. Note Vref is also onchip and OpAmps
for scaling if you need them.

There are two low end boards, CY8CKIT-042 and 049. Former is $ 25,
latter is $4. Latter requires buying a dongle to debug, former debug
facility on board. Both program via USB.

Tool, PSOC Creator, and compiler free.

All parts ARM core, low end ARM M0, high end ARM M3, latest dual core
ARM M0+ and ARM M4, PSOC 6.

Note example shown operates SAR in single ended mode. Differential is
configurable as well, just takes more pins, different package because I
used some pins for LCD in example.

Note if you do this with higher end parts, PSOC 5LP family, or low end
PSOC 4M family, using DMA this can be totally done as a background
process, with A/D stuffing UART after each sample taken. Also if you
prefer Bluetooth there are parts that can handle that stack as well.

Regards, Dana.


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