Timeline for PH interfacing to ADC
Current License: CC BY-SA 3.0
6 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Oct 19, 2011 at 18:14 | comment | added | user623879 | Might end up using this: ti.com/product/ina116#samples | |
| Oct 19, 2011 at 18:08 | comment | added | user623879 | Wish i had the probe and access to a decent scope lol..but I want around 3-10ph range, or -240mV to 180mV range....ph probes by their nature require extremely high impedence..even nA currents can cause significant error. The interface device requires on the order of pico or even fempta amp input bias. | |
| Oct 19, 2011 at 16:41 | comment | added | Olin Lathrop | @user: You still haven't characterized the probe signal. What pH range? What probe voltages does that correspond to? At what impedance? | |
| Oct 19, 2011 at 16:36 | comment | added | user623879 | This may turn into volume product, and I am going to use standalone ADC...not overly worried about gain at this point, can fine tune that with some testing. With instrumentation amp, looks like a reasonable thing to do, though it is a bit more expensive, but do I need it? I only need res of around .01pH. This is hard to know without trying it | |
| Oct 19, 2011 at 16:23 | comment | added | user623879 | Am using LMC6041, see annotation on image-->my sim tool does not have very many parts. | |
| Oct 19, 2011 at 12:43 | history | answered | Olin Lathrop | CC BY-SA 3.0 |