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Sep 5, 2018

New Guy with Dome


My name is Ron and I live in Celina, Texas. Been an imager for a long time using ACP. I am happy to report the Pat M's latest Github plays well with ACP as the client. Mount and Dome danced together for the first time nicely tonight. Version 05.2.3 PDMRotator, PDMShutter, and ASCOM PDMDome0523Setup. I am unclear about the voltage setting in the setup tool. My controller drops to very low voltage when not active (rotator) and unless I set low voltage threshold to something like 5.8 ACP will disconnect from too low voltage. I'll try a different power supply for the rotator..


The Rotator compiled clean. The shutter uploaded but complained of missing items. Now that the Dome itself might actually be ACP-ready chasing down the shutter is next priority. Any obvious gotchas folks know about pass my way. Pat!! I'd love to have a good way to interact with you about this. I did re-up Facebook just for the NexDome group but all my IT friends say to stay away. I'll do what I need to do to get all of this talking well! I'm really excited to have the Dome, find this group, and watch it track objects as a slave to ACP.

Sep 25, 2018

The voltage shouldn't change between active and non active as it takes the 12V input and run it through a voltage divider using the 3 resistors then feed this to the A0 (analog 0) pin of the Arduino.

5.8V is not normal, it should be around 12V and can drop to 11V or slightly less if the power is a battery.

Can you check the board to make sure all 3 resistors are in place ?


Sep 25, 2018

Thank you very much! I will do so. The Great news is that the dome/shutter have been working perfectly in unattended automation with ACP as client program. I had set the minimum voltage in settings ( to 1V.

Sep 25, 2018

Here is a picture I took when the controller arrived. Where might I look for the resistors? I see the power in (red/black).


Sep 25, 2018

I see the 3 resistors on the board :



So either one is not properly soldered (things happen as we say) or they are not the proper value.

They should be all 1 mega ohm ( Brown, Black, Green, Gold), or at least all 3 should be the same.


Sep 25, 2018

Thanks! I'll poke around with my volt ohm meter and see what the story it has to tell. Thanks for the detailed information!!

Sep 25, 2018Edited: Sep 28, 2018

Ok, This is the schematics for that part :


On the board picture, R1 is on the right, R2 on the left and R3 in the middle.

You should get about 4V between GND and VPIN (12v /3 = 4v).

New Posts
  • This is the process i go through to get to the speed settings for the shutter, so a few questions: First I open ascom dome control panel I click connect. Of course it doesnt let you change values unless its disconnected, so i disconnect and reopen the nexdome ascom server monitoring window, hit setup: Seems no matter what values i put below, here 600/1500 etc, the speed of the shutter is the same. I had tried lowering these at first to see if it would help with the motor sticking. Is this the right procedure to lower the values and test? Also, i know there is a much longer thread here about updating the firmware on the shutter/rotator, but, what does the update firmware button here do? At one point i clicked it when only the rotator was connected, it claimed it updated? How do i know if i even need to update either? Both came brand new recently? Thanks in advance
  • I've completed the motor install (although i may be missing parts on the motor related to this, the set key that holds the pin in place was missing, found an m4 for now that seems to hold it but the pin doesnt go in fully, see this thread for more details) First issue (or maybe not), when i push the motor and it moves up, i think when the panel that has the band through it goes under the first panel, half way up, it sticks for a half second, flexes and pops and keeps going. After this at times on the way up, even during the first half, sometimes the motor stalls briefly. The biggest issue is after its up fully and you bring it down, the first 16" or so going back it stalls and moans repeatedly, however, interestingly i can work it forward by doing an on off real quick multiple times, OR by pressing upward on the motor. Here is a video clip of the stalling (most of it near the end): At this point i took all the wheels off the rear, added washers, so now they have quite a bit of flex available. The retention bracket is installed, but i had my son work the motor while i pulled back on the bracket and wheel on one side only, no change. When you pull the panels in the rear when its up there, apart, you can see grinding marks on each panel on the sides. So at this point i'm left with removing the retention brackets on both sides as a final test, and to be able to get the panels apart to add antifriction tape someone recommended. It appears the front panels will need to come off (not the rear solid non moving one), then apply tape as here: Here is an external view of the situation: This is the antifriction tape i've ordered (1" x 15 feet, two rolls,TapeCase 423-5 UHMW) : I dont know what else to try, other than what i have planned at this point. Pretty frustrated. Incidentally, i have the inside dome rotation working pretty solidly, so this is the only sticking point, pun intended. Thanks in advance.
  • Im breaking my shutter issues into multi parts here, in this one, i seem to be missing the set screw on the part by the gear as in this image: The part circled was naturally coming out. I'd like to get the official part to fix this, however in the meantime i've added what seems to mostly fit but not flush, m4 set screw and the locking pin goes in a tad further: Any suggestions here? From someone else, it appears that pin should slide all the way inside (i dont know if this could be related to the motor stalling/sticking issue i have (sep thread))