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Old 06-26-2009
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roline roline is offline
Cal 9.2 SilverSwan
 
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DMI transducer to Raymarine ST60 adapter

I'm in the process of trying to adapt the existing DMI speed sensor to a ST60 speed display. The DMI is a small signal magnetic reluctance unit and the Ray is a Hall effect with 0-12 volt signal.
I designed and ordered a PCB, removed components to simplify. Just need to install it on the boat and verify the calibration range on the ST60.
Has anyone tried to do this interface???
First attempt did not properly energise the transducer. Had to add a current source to allow the transducer to pull down when it trips. I took the DMI display apart and traced the circuit out to duplicate. I added a new input stage to the existing board, not a pretty site, but does work with the same sensitivity as the DMI unit. I like the DMI transducer with the wider paddle wheel blades, more sensitive at low hull speeds than the RM brand.
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File Type: jpg DMI_RAY.jpg (76.7 KB, 44 views)
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Last edited by roline; 07-12-2009 at 11:25 PM.
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