ESP8266 Community Forum

- Sun Jul 30, 2017 2:56 am #68704 I have one of these from Ali:
https://www.aliexpress.com/item/1PCS-X- ... 0.0.QhyPjQ

For some reason I presumed hooking it up to the ESP would be easy. Turns out I have no idea with a 4-20Ma connection is.

Any pointers please to get me started? I am stuck even what to google.

thanks

- Sun Jul 30, 2017 3:35 am #68707 why not use the 0-5V output and use a voltage divider to get the 0-1V needed by the esp?

the 4-20mA would give you 0.2-1.0V on a 50Ohm resistor to gnd, also compatible with the esp adc input.

- Sun Jul 30, 2017 8:52 am #68716

Turns out I have no idea with a 4-20Ma connection is.

While the Chinese are excellent in copying stuff, their use of correct English, magnitudes ("Metrix Prefix") and SI Units is appaling.

What the text actually says is: "[...] current in the range of 4mA to 20mA" (where "mA" stands for milli-Ampere)

Assumption is the mother of all f*ckups. At least: that's what I'm assuming.

- Mon Jul 31, 2017 12:41 am #68732 Thank you, went the 5v option, worked a charm.