Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
eiaro said:I'm working on making a 4-20mA data logger, but since I'm not the only one on the loop I wonder how to proceed without opening the can of grounding worms.
If anyone had experience on how to do this, I'd appreciate the input.
eiaro said:I have to take into consideration that the signal might not be 4-20mA, but actually 0 to 25 mA. Since I'm also going to use this on more than one loop, I'll keep the voltage drop lower and adjust the gain on the opamp. I know that the original intended loop has no problem with another 250ohm load.
The shunt resistor is 20ohm, the gain on the opamp is close to 10x. This should give me 0-5V for 0-25mA.
The attached circuit is my design using LT1789. I'm still concerned for the input bias currents.
Do you have their permission to use it?eiaro said:Since I'm a parasite logging someone else's loop, I will prefer to see the errors as well.