# connect an impulse sensor

Hi All,

I would like to build an arduino based electric consumption project. I have already selected the sensor

http://www.elmarkholding.eu/ru/Din-Rail_Mounted_kWh_Meter_DDS-1Y-45/p353.html

but i don't know hot to connect it to the ardunio in a safety way.

Could you please show me a sample circuit?

Not much useful information in the data sheet. The device outputs 1000 pulses per kWh consumed, but at what voltage and maximum current?

Hi!
Thanks for the replay!

As i see in the data sheet output is 12-27V and < 27mA and 90ms. I think i can not connect it to the arduino directly.

However, you can make a direction connection, using a voltage divider.

If the voltage is 27V, then a 6:1 divider would work (e.g. 50K and 10K ohm resistors).

If the voltage is 12V, then a 3:1 divider would work (e.g. 20K and 10K).

The latter divider can also be used with the higher voltage, if you add a 5V Zener diode in parallel with the 10K resistor, to limit the voltage input to an Arduino pin to 5V.

I didn’t find those 12-27V / < 27mA / 90s values, neither in the device datasheet nor in the general device family datasheet.

What I did see in the datasheet is that those devices have an open collector S0 Interface, which is the usual interface for power meters in Germany: S0-Schnittstelle – Wikipedia (Content available only on the german language Wikipedia.)

Your counter is probably specified for at least +12V, but most of the devices are fine with 3V3 or 5V.

Connect S0- of the Counter to Arduino GND and S0+ to any free Arduino Digital Input pin and
activate the internal pullup resistor.

Your Input pin will be in HIGH state most of the time and you will see counting impulses (probably with 90ms duration) as LOW.

This information is provided as-is, I’m not responsible for any damage caused by it.

Thank you all of your help!

I am going to try it.

Anyway i have already bought the sensor and i got a piece of paper with it as a data sheet :) with the information that i shared. I bought it at Hungary so it was in hungarian that is why i did't share it.