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/ Vixen DMD-2 and DD-1: intercha...
Vixen DMD-2 and DD-1: interchangeable?
October 8, 2013 2:32 AM
Before I go plugging something in to something else and accidentally releasing the magic smoke supply, I wanted to confirm whether or not the DMD-2 and DD-1 controllers and associated motors are, in fact, interchangeable? I believe that they are, but wanted to get confirmation. I am buying another older Vixen mount that is coming with dual motors and a DMD-2 controller, and would prefer to use a DD-1 controller with it. I have an extra DD-1, as well as a DD-1 that's modded for autoguiding, hence the question... thanks in advance for replies.
October 8, 2013 3:09 AM
I have a DMD-3 controller and it is compatible. The circuit board is actually labeled DMD-2. So not totally sure about the DMD-2. Vixen changed the gear ratio and voltage on the motors to improve slew times on GOTO systems. When they did they changed the motor cable connector from 5 pins to 8 pins. If the motors on this mount have 8 pins they will work with the DD-1. If only 5 pins then no good.
October 8, 2013 3:14 AM
they are both stepper controllers, but one has a 5-pin and the other an 8-pin plug. if the plugs are the same they are probably electrically identical -
the DD-1 (I used to have one) uses the 8-pin DIN plug. Some ads/posts on the internets leaves me to believe that the DMD-2 can drive the MT-1.
but if you're in doubt, use a multimeter to check the wiring on your new motors. these are ordinary unipolar steppers so easy to figure out (use the pinouts from the link above).
October 8, 2013 5:06 PM
Thanks. One mount with 8-pin connectors uses the DD-1, the other the DMD-2. I didn't recall their being any difference between the two. However, I wasn't sure if the steppers had a different degrees/step rating or not. Only way to check, I assume, will be to disassemble the entire system and check them.
I know there's a difference in the go-to motors as they're closed-loop with built-in encoders (I used to have one) and I think they're servos rather than steppers anyway.
October 8, 2013 8:14 PM
There's no difference, they're both 48 ppr Nippon Pulse tin cans. Not sure if the gearing is different though (the DD-1 uses 120:1 gearboxes). But gearing differences wouldn't release the magic smoke.
Definitely the GoTo (except the original SkySensor) uses different motors. The 48 ppr, 120:1 motors are too slow for GoTo, running full-bore they can only do 40X sidereal or so.
October 9, 2013 11:19 AM
Tony White --- 18" f/4.43 Pegasus/homebuilt dob TMB 152 - TMB 105 - AP 105EDF - Antares 105 Elite - Jaegers 110/495 - Celestron C102F - Celestron C80F - Brandon 80 f/6 - AstroTech AT72ED - Some Unitron Stuff Celestron Ultima 11, Orion Optics OMC-140, Celestron CometCatcher AP1200GTO - AP400GTO - Vixen SP-DX modded - DiscMount DM-6 - Lapides Tak Teegul - AstroTrac Garrett GT100-45, Celestron 11x80, 9.5x44ED & 6.5x44ED, Eagle Optics 10x50ED Canon 450D and Nikon lenses
/ Vixen DMD-2 and DD-1: intercha...
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