Nathan Meeting Topics Current List -Nov-2022 -------------------------------------- 1. What is the official name of the PMT mounting board ? 2. What do you officially call the PMT mounting brd that is on the "top" side of the Disco-Kraken brd vs the PMT mounting brd that is on the "bottom" side of the DK Brd ? 3. Is the rotational orientation of the PMTs (about the long cable axis: controlled ? stable ? measured ? Do you care about their rotational orientation ? 4. PLL 5. Mechanical Only Model - may be useful in this case, examples of what we have done before. 6, Purchase of "engineering sample" of all parts on the board. Start a whole bunch of questions about the design of the Grounding system for this DAQ System. I have many concerns for example - is the Ocean Ground that is just an inch or two from the PMT Cathodes at a stable potential wrt the PMT Cathodes ? How do you run the PMTs ? Cathode at Gnd and Positive HV on the Anode or Negative HV on the Cathode with Anode at Gnd going into the ADCs ? 7. What is the input power to the Disco-Kraken board from the base on the ocean floor ? e.g. is it AC or DC ? If it is AC what is its Common Mode voltage with respect to the local "Ocean Ground" and is that stable ? If it is DC then is for example the negative side of the input power at the same potential as the local Ocean Ground ? Is the potential of the local Ocean Ground at the base of the string the same as it is at the Top of the string ? 8. Is the central metal ring of the module, which touches the ocean, connected to the Signal Ground in the module ? E.G. Should the mount points on the DK pcb electrically connect to the central metal ring or be isolated from the central metal ring ? 9. Is there a wire in the long cable that connects together the Signal Grounds in all of the modules that are in a string ? 10. Everything inside a module could be (or could almost be) isolated from any Ground connection in the long cable: - Input power can be isolated. - Optical 1 Gbps Enet / Timing is isolated. - Copper 10 Mbps Enet can or is transformer or capacitor isolated. - Copper LVDS Timing - can this be AC coupled or not ? Is it a DC Balanced protocol ? 11. The Signal Ground for everything inside a given module could be at the local Ocean Ground potential (via the central metal ring touching the ocean) and could float wrt the Signal Grounds of all of the other modules. 12. What concerns are there about corrosion of the central metal ring where it touches the ocean ? 13. Within a module - what is the official ground design for isolating (or at least isolating the noise on) Signal Ground vs Digital Ground vs Power Return ? Do you need common mode chokes on the differential analog inputs to the ADCs ? Other Topics: 14. How will you use the DDR Memory on the CPU and on the FPGA ? My understanding is that you need DDR Memory on both of these ? My understanding is that your Demo Brd has DDR Memory only on the CPU. How much and what speed memory ? How much power has been allocated to the DDR Memories ? 15. I'm still understanding how you Program this FPGA/CPU and exactly how it starts up at power up time. One option seems to involve an external SPI Flash Memory connected to Bank 3. Does the DK board need such a memory ? I assume that the DK board needs the 10 pin header that has the dedicated JTAG connection (plus some other stuff) to Bank 3 of the FPGA/CPU. How is this external "emergency recovery" thing from the Germans going to connect to the DK's FPGA/CPU to program it or to reset it ? 15 / 95 = 0.158 ML