2017-03-08, 11:29 AM
(This post was last modified: 2017-03-08, 12:30 PM by affinite.
Edit Reason: add dwgs
)
Thanks in part to PaddyB I now have my tank levels in NodeRed displaying wonderfully.
I do have a problem accurately measuring the input voltage to the MCP3008 ADC and wondered how others had dealt with this.
I am using a simple voltage divider with my 0-190 ohm resistive tank senders to send a measured voltage representing the tank level to the ADC. The problem is that this is susceptible to variations in the supply voltage which can cause inaccurate readings on the ADC.
The second problem is that at a supply voltage of 5v with a (lowest) resistance of 100 ohms each voltage divider is drawing around 50ma. I have 4 tank senders so Im drawing 200mA just for the senders.
Does anyone know a better way of sending the tank levels in a way that is more accurate and draws less current ? I assume Im talking about OpAmp circuits but I'm not capable of designing my own circuits so any help appreciated
Thanks
Steve
I do have a problem accurately measuring the input voltage to the MCP3008 ADC and wondered how others had dealt with this.
I am using a simple voltage divider with my 0-190 ohm resistive tank senders to send a measured voltage representing the tank level to the ADC. The problem is that this is susceptible to variations in the supply voltage which can cause inaccurate readings on the ADC.
The second problem is that at a supply voltage of 5v with a (lowest) resistance of 100 ohms each voltage divider is drawing around 50ma. I have 4 tank senders so Im drawing 200mA just for the senders.
Does anyone know a better way of sending the tank levels in a way that is more accurate and draws less current ? I assume Im talking about OpAmp circuits but I'm not capable of designing my own circuits so any help appreciated
Thanks
Steve