Richard H

@attila Just checked back, saw @JColvin 's response the other day - Thanks both! Richard

Hi @attila Many thanks for the resistor locations and forum link - much appreciated. Super handy page - I might get myself a spare ADG612 just in case from your comments there!! PS. might be mistaken, but are V- and W2 at the other end of the header pin bank? Giving it a little thought, I might go with an amplifier on the shunt add-on board in any case, ~1v of signal is a heck of a lot from a shunt - and debate if more sensitive inputs on the AD2 would be ever a useful thing in due course. No problem in swapping a few resistors on an external amplifier in the future, perhaps! Thanks again for advising on my postulating, Richard

Hi @attila Thanks indeed for your quick comments. Feel free to take your time to get back to me on the below / tell me this is a terrible idea. I saw the ADP3000, sadly out of my price range! I'd prefer to avoid an external amplifier if possible (I have various other applications that might benefit from enhanced low signal fidelity) but it's certainly an option I will consider carefully. My shunts would be on a custom add on board, right alongside the AD2 in any case. I see your points about issues with changing input capacitance, altering signal paths (?) to accommodate resistors, or adding extra amplification. One possibly tidy route I thought was to add another ADG612 on a small PCB hovering over the existing one, arranged as a third "selection", except this time coupling full input signal through, rather than a fraction of the full input signal (with a resistor for clamping). Avoids e.g. horribly rerouting the original signal paths via wires at least. Is it possible to turn off both EN_HG_SG1 and EN_LG_SC1 (and same for SG2) from software - I presume from one of your posts elsewhere, probably not? Alternatively, if I could spot the locations of R26 and R27 (and analogous for the other scope channel), I could switch off these two channels manually and arrange the other IC to mutually turn it's signal paths on in this condition. I suppose the downsides of this, apart from the implementation, is the capacitance from the extra IC (probe trimmable?) and parasitics from extra connections. At least the latter are short and kept well away from noisy board areas. Best wishes, Richard

Hello, New owner of an AD2 here, musing of possible applications. Has anyone considered or asked about modifying the AD2 for better low level signal sensitivity on the analogue inputs? One idea I have in mind involves high current sensing, and the 5V low range on the AD2 would need many watts dissipating in a shunt to make full use of the ADC range (if I am understanding the AD2 capabilities correctly). Looking at the schematics in the reference manual, I thought: - figure 3, adding a switched parallel R (say, 22k or something, so the ESD diodes can still act as clamps) with appropriate capacitor across R1/C1 and R24/C24. Guess this would be at the expense of no longer having a 1Mohm, 22pF input, and some fine tuning of the capacitor value to get the input response about right again. - figure 4, adding switched resistors to the scope buffer to generate amplification (at the expense of also amplifying noise) - (external amplifiers are also an option, but adding value to the AD2 would be my preferred route!) Of course, the current sense resistor needs to be down near the AD2 system ground, for this to work. Just a few thoughts off the bat, and my apologies if this has already been discussed elsewhere, or if there are simple software settings I should instead be changing. Apologies also if implementing either of the above are actually much more complex propositions than I am appreciating! No particular rush, but it would be good to hear thoughts on the above - yet to have a proper play with the AD2. Thanks in advance, Richard