ADC Specifications

I’m considering using the single relay ethernet board with 8 channels of analog to digital conversion (part number: R15PL_ETHERNET). I require futher details on the ADC. Specifically the input impedance. Also I require futher understanding of the 8 vs10 bit resolution. A part number or data sheet on the ADC would be welcome.


Hi Tim,

We use this chip for the ADC on that board:

The impedance can be found in that datasheet. In addition there is a jumper to pull the inputs high or low, we use a 10k resistor to do this.

Can you explain the information you’re looking for in regards to the difference between the 8 and 10 bit resolution?


Thanks for the PIC info - very useful.

As for the resolution - I do not understand listing the resolution as 8/10 bits. Is the resolution 8 bits or 10 bits or maybe user selectable? There is no information on this matter that I can find. Can you explain the resolution available with the R15PL relay board?


Reviewing the PIC A/D information in the data sheet you referenced, 10 bits seams to be the resolution of the A/D. Why is 8 bits mentioned, and why have sales people told me the R15PL A/D has resolution in 255 increments, when 10 bits should give 1024 increments?

The ADC data can be either, it depends on what command you use to read the data. This will be covered in the guide as to which commands to use for what:

I believe we convert it down to 8-bit on the board to reduce the amount of data transferred, but @ryan would need to give you the definitive answer there.

If you request the 8-bit A/D data it will return a value from 0-255, if you request 10-bit data it will return a value from 0-1023.

This was answered on a ticket that was submitted in duplicate to the posting on the community.