johnMi 2 Posted July 14, 2011 Share Posted July 14, 2011 I have the above system where the display is stuffed. I am getting an Imux multiplexer to connect to my iPad, but I need some advice about the 3 wires going to the speed transducer, and the two to the depth. If I just go by trial and error, can I cause damage Link to post Share on other sites
Farrari 4 Posted July 14, 2011 Share Posted July 14, 2011 I have the above system where the display is stuffed.I am getting an Imux multiplexer to connect to my iPad, but I need some advice about the 3 wires going to the speed transducer, and the two to the depth. If I just go by trial and error, can I cause damage Have you seen this? Given the exchange rate it might be worth a look. http://halifax.kijiji.ca/c-cars-vehicles-boats-watercraft-parts-trailers-accessories-RAYMARINE-AUTOHELM-ST30-BIDATA-WITH-THRU-HULL-TRANSDUCERS-W0QQAdIdZ291335978 AUTOHELM ST 30 BI DATA WITH NEW AIRMAR ST600 AND P319 THRU HULL TRANSDUCERS for $225 Canadian. Link to post Share on other sites
johnMi 2 Posted July 14, 2011 Author Share Posted July 14, 2011 That is a good price! However, I contacted Brookhouse and he's setting me up with a Multiplexer to use my iPad. All I need now is to connect the transducers to the iMux. Link to post Share on other sites
Farrari 4 Posted July 14, 2011 Share Posted July 14, 2011 That is a good price! However, I contacted Brookhouse and he's setting me up with a Multiplexer to use my iPad. All I need now is to connect the transducers to the iMux. Are you sure your depth and speed ST30 transducers are NMEA 0183 compatible? I would have expected more wires if they were. NMEA is a RS422 or RS232 compatible interface so will need two wires for the signalling plus power. If its a combo then you will need more again. You can probably connect the NMEA 0183 interface from the ST30 head unit to the iMux even if the display isn't working. Link to post Share on other sites
Gappy 9 Posted July 14, 2011 Share Posted July 14, 2011 I would say the transducers are not NMEA capable becuase as Farrari said you should have more wires I would expect something like 5-7 wires for that Link to post Share on other sites
Battleship 100 Posted July 14, 2011 Share Posted July 14, 2011 Wouldn't a NMEA transducer only need ground +power and +data out? Link to post Share on other sites
johnMi 2 Posted July 14, 2011 Author Share Posted July 14, 2011 Errr.... I am sure I read it was NMEA 0183, then I looked for the info again and can't find it. Might have to rethink..... Link to post Share on other sites
Farrari 4 Posted July 15, 2011 Share Posted July 15, 2011 Wouldn't a NMEA transducer only need ground +power and +data out? Potentially you could get away with only three wires minimum but it's not the way it should be implemented. NMEA 0183 uses a RS422 interface. RS-422 is backward compatible with RS232 but RS-422 uses a balanced signal where RS232 uses a signal with reference to signal ground (unbalanced). This means the voltage difference between the two wires is what is important, not the actual voltage with reference to ground. This helps with noise as induced interference would normally affect both wires so the relative voltage between the two does not change. You can run RS-422 greater distances on lower voltages than unbalanced RS232. RS232 should use a different signal ground wire to frame ground. Normally they tie the two together with a 100 ohm resistor or something similar. If you take RS422 and tie one wire to signal ground you can interoperate with RS232. Link to post Share on other sites
Battleship 100 Posted July 15, 2011 Share Posted July 15, 2011 thanks for that Farrari, interesting subject. Anyone know of any reference available for the different types of protocol used by different manufacturers? I don't understand why they can't all use the same language would make connecting things alot easier. Link to post Share on other sites
johnMi 2 Posted July 15, 2011 Author Share Posted July 15, 2011 Willow They only want you to be tied to their system and that's the issue. No chance to mix and match. Link to post Share on other sites
Battleship 100 Posted July 15, 2011 Share Posted July 15, 2011 Yes I guess if they all used nmea they would have to rely on silly things like quality and service to sell their hardware. Link to post Share on other sites
morspeed 1 Posted January 28, 2013 Share Posted January 28, 2013 I have the above system where the display is stuffed.I am getting an Imux multiplexer to connect to my iPad, but I need some advice about the 3 wires going to the speed transducer, and the two to the depth. If I just go by trial and error, can I cause damage I have exactly the same problem..Bidata head unit is fried..as far as i know the speed sender and depth transducer are fine.. How did you resolve your issue..did you get the ipad communications resolved? Cheers..Gary Link to post Share on other sites
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