Connecting electronics

[roly_voya]

I now have most of the electronics in boxes in garage ready to fit after christmass but have been looking at how to wire it all together /forums/images/graemlins/confused.gif /forums/images/graemlins/confused.gif

I have a JRC JMA-2343 which should connect to GPS, heading sensor and send out the curser position. Also have Garmin GPS172, raymarinte ST400+ autopilot and will be using a Dell laptop for nav which doesnt have a serial port (has lots of just about everything else!!!).

1 - I want to connect the GPS to both the radar and the laptop so that they all share the same way-piont database?
2 - The 'dataout' for the curser display is two wire (data +&-) but there is no indication in the manual how you feed this to a computer?
3 - Againe the heading sensore has two conections +&- do these hook directly to a heading sensor or to the NMEA conections of the autopilot head?
4 - Should I be looking to make all the connections as individual links or would it be better to get sothing like a NMEA hub and connect everything to that and let it sort out who wants what data?

I am reasonably good with electrics but never done anything with NMEA networks - is it reasonable to expect to be able to do this or should I call in an engeneer to set it up?

 

[wotayottie]

Only the PC should be difficult - all the others are made to connect together and the details should be in the instructions.

If you search this site there have been previous queries about PC connections which involve connecting to a serial connector and then via a usb/ serial convertor - I know because I have done it successfully. Unfortunately whilst I have the cable I made up, I dont have the wiring diagram to tell me which connector of the serial plug takes the NMEA signal..

Sorry I cant be more helpful, but I certainly can confirm that it isnt something you need to hire an expert to do.

 

[Jonny_H]

I would imagine:

GPS: NMEA Out (+ / -) into a choc block and feed to radar (GPS NMEA In)/ computer / autopilot (NMEA Nav IN) (if necessary)
Heading Sensor: NMEA Out (+ / -) into a choc block and feed to radar (Heading In) / autopilot (Heading In)
Radar: Connect cursor Out to computer (NMEA IN).

The problem will be getting two NMEA Inputs to the computer (one for GPS and one for cursor position from Radar). Why do you need the cursor position on the laptop? In terms of wiring for the laptop - wire NMEA to a serial cable (search forum as the connections have been mentioned in the past) then use a USB / PCMCIA converter to connect serial to laptop.

Hope this helps

Jonny

 

[iangrant]

A small but frustrating can of worms
To get into the laptop you'll need a serial to USB cable/driver.
From your gps output all the other devices should be "listners" so as long as they are the right wat round (trial and error) it should all work, If uyou have any seatalk then you'll need a seatalk/nmea box.

Ian

 

[bobgosling]

One of this month's Sailing mags ( Sailing Today I think ) has an article about a NMEA multiplexer which includes a USB connector. Quite pricey but "proper" kit. Have seen them on JG Technology's web site here

 

[Danny]

Seems to me like you'll need either a multiplexer (and one serial/usb converter) or two serial/usb converters for your PC. You can't just splice the GPS output and the radar cursor output together. They either need to be multiplexed and fed into one serial port or else they need to go to seperate serial ports on the PC.

How will you use the cursor position data in the PC? If you want your nav software to display the radar cursor position on the chart it'll need to support the nmea TLL sentence. Also you'll need to check if the s/w supports two serial ports - if not you'll definitely need the multiplexer.

I thought the st4000+ had its own fluxgate compass (with a 4 wire connection to the instrument head). If so you don't need the nmea from the heading sensor to go to the a/p.

Hopefully the radar has seperate inputs for GPS and heading sensor/compass.