SDSU (ARC) CCD controller documentation

29 November 2018

(and updated SDSU PSU section at end on 12/11/2023)

Following Dave Atkinson's visit to Thailand, we realised that the documentation for ULTRASPEC is in a dire state. To rectify this, Dave collated the following set of circuit diagrams and user manuals for the CCD controller boards in ULTRASPEC, as well as providing a change history document. Note that all of the drawing versions should now be correct with the exception of the power control board (ARC73). Bob Leach does not have any 6B documentation on file, but he suggests that 6C will be as good as "identical".

I've now also added the circuit diagram for the SDSU PSU (ARC80) that we use for both ULTRASPEC and ULTRACAM. I also added updated information on PSU situation and the spare CCD controller, following Dave's and my visit to the TNT from 23-29 Nov 2018.

On 12 Nov 2023 I added some new text to the SDSU PSU section at the bottom, in light of the PSU testing and general sorting out I did at the TNT on this date.

ULTRASPEC has the following boards in its 6-slot chassis:

The drawings and manuals for the various SDSU boards are below:

  1. ARC22r5D_Layout.pdf
  2. ARC22r5D_Sch.pdf
  3. ARC32r6A_Layout.pdf
  4. ARC32r6A_Sch.pdf
  5. ARC32_UsersManual.pdf
  6. ARC45r3B_Layout.pdf
  7. ARC45r3B_Sch.pdf
  8. ARC45_UsersManual.pdf
  9. ARC73r6C_Layout.pdf
  10. ARC73r6C_Sch.pdf
  11. ARCControllerHistory.pdf
  12. ARCControllerHistory.xls

  13. ARC-22: 250 Mhz Fiber Optic Timing Board, Gen III: User Manual

During visits in Nov 2017 and Nov 2018, Dave and I configured our spare SDSU 6-slot chassis with the following spare set of boards:

We use an ARC80 (large) PSU for ULTRASPEC, the same as we do for ULTRACAM. We currently have 3 of these SDSU PSUs in Thailand. These are:

I have 3 SDSU PSU cables. Two are 10m long and one 5m long. One of the 10m long ones is currently being used on the instrument. It is showing some signs of wear in its outer sheath where it rubs against the NARIT cable twister, so I may have to replace this with the spare in the future.

Update on SDSU PSUs and cables on 12/11/2023 during TNT visit by VSD:

I brought out a new SDSU PSU and 10m PSU cable to the TNT with me on this visit. These are the final purchases I made from Bob Leach in Feb 2023 before he closed his company down for good (due to his retirement) - hence it will be impossible to order any more in the future. I tested the new PSU and 10m cable with ULTRASPEC and it works perfectly. In order to be consistent with the previous naming scheme, I've named the latest PSU the Newest SDSU PSU and stickered the PSU and its box accordingly (and similarly the 10m cable and its box), and put them in the ULTRASPEC crates.

The Old Spare SDSU PSU had been in use since March 2017, but on 6 November 2022 it failed (it was unable to PON), and was replaced with the New Spare SDSU PSU. I decided to check the Old Spare SDSU PSU during this visit and found to my surprise that it worked! Weird - the previous error must have been a glitch (it occurred right at the start of the 2022/23 observing season when the system was powered on for the first time in months, so maybe that explains it). I put the Old Spare SDSU PSU back in the crates, removing the "broken" stickers from it! I decided to leave the New Spare SDSU PSU in the rack as this possibly shows a slightly lower RNO and pickup (but marginal). Note that I stuck the G10 insulation mounts on the underside of the New Spare SDSU PSU to ensure they don't slip off, and found the best RNO is when the PSU is slid slightly back from the rear of the rack unit it is in - you need to make sure it doesn't make contact with the sides to prevent ground loops. (Only the Old Spare SDSU PSU has threaded holes in its base for the G10 insulation mounts - I left the nylon bolts for this in a bag taped to the inside of the PSU 4U rack unit it is mounted in.)

This left one problem - I could not find the Original SDSU PSU anywhere at the TNT! On checking my emails I realised that Apichat sent 2 boxes back to me in the UK after Dave Atkinson and I visited the TNT in November 2018. One box contained the PSU I bought from Bob Leach in 2017, which didn't work when we tested it with ULTRASPEC and which I gave to Dave in return for him leaving his SDSU PSU, which did work, out here at the telescope in Nov 2018. Dave's PSU then became the New Spare SDSU PSU described above. The second box Apichat sent back to me contained the Original SDSU PSU and the faulty SDSU Timing Board described in the description above of Slot 6 of the spare SDSU controller. I returned both to Bob Leach for repair in Feb 2019, intending to return the Original SDSU PSU to the TNT to act as a (fourth!) spare PSU, and the timing board back to Dave in Edinburgh to pay him back for giving me his UKATC timing board (the one currently in slot 6 of the spare SDSU controller). Bob Leach received the items and reported that neither were broken and both seemed to work fine - weird. I had a bit of email to-ing and fro-ing with myself, Bob and Dave, and then silence after Mar 2018. I completely forgot to chase this up with all that was happening with HiPERCAM at the time, and then completely forgot about it, until now. So I believe what has happened is that Bob never returned the Original SDSU PSU or the timing board back to me, and now Astro Cam has closed down for good and Bob Leach has retired and these items are lost forever. Damn. So this means we have only 3 working SDSU PSUs for ULTRASPEC, not 4, which is fine, and I owe UKATC a timing board...

So, in summary, we're now operating with the New Spare SDSU PSU. We have 3 working SDSU PSUs for ULTRASPEC, and we now have 4 SDSU PSU cables - three are 10m long and one is 5m long.