#Nmea 2000 network cable pdf
Meanwhile, Maretron’s Micro/Mid Powertap Tee ( PDF here) is truly split (as is the Actisense QDP), which also helps with the issue of voltage drop in a large N2K network. Note that Maretron obviously sources their Mini Powertap ( PDF here) from the same source, except that theirs has two female backbone connectors, so that if you ever open the network live, the male pins shouldn’t be hot (unless the gender was changed somewhere). But testing - and the further research I should have done in the first place - indicate that both power feeds go to both sides of the network, enabling redundant power sources instead of splitting the trunk. I presumed that the two pairs of power leads meant that I could separately switch the two sides of the trunk line, as explained here on Panbo. I was also disappointed with this surplus DeviceNet power tap, though it’s built like a tank. At first, I thought they could be used with a raw wire junction box like Furuno’s or Actisense’s, but the cable is also UltraThin size with 26AWG wires, which is not up to N2K specs. (Turck calls Micro size connectors Euro or EuroFast, by the way, and there are many such impediments to eBay search and identification.) At any rate, there are hundreds of these cables available on eBay for some reason, sometimes for as little as $5 each. Doesn’t that look like a nice 0.8 meter Micro drop cable with a 90° female end handy for attaching to the back of many N2K devices? Well, look a little closer, because that male connector is not Micro size, but rather an even smaller DeviceNet standard size, variously called Nano or Pico. Heck, you could just use the Micro ports for all the connections, though it would be a bad idea to leave the Mini port contacts exposed (fine Turck male RKF-MC and female RSF-MC closure caps are available surplus, and there are probably many alternatives if you can find them).īy now you’ve probably realized that yours truly spent part of his winter collecting components for an N2K network that may be heavy duty enough to run a serious assembly line, but before discussing further, let’s look at a couple of mistakes. I’m also demonstrating how you can check for the proper 60 Ohm resistance across the white and blue data wires, because you may recall that NMEA 2000 is an impedance-driven networking technique.
![nmea 2000 network cable nmea 2000 network cable](https://amimarine.com/wp-content/uploads/2020/09/A2K-KIT-2-6m-cable-NMEA-2000-Starter-Kit-2-ACT-0026.jpg)
In this case the JBBS is the entire backbone with 7 female Micro connectors ready to accept drops up to 6 meters long each. But in the photo above, I’m using one Mini to insert 12v power with terminating resistors screwed into the other Mini and one Micro port. So the Turck JBBS 57-811 junction box is designed with male and female Mini ports for the network trunk and 8 Micro female ports for device drops. Apparently, that’s also a common connector architecture for industrial automation, which explains the design of the Turck junction box and the preponderance of Mini size cabling when searching eBay for DeviceNet cable listings. I’ve only seen the misnamed Mini connectors - they’re 7/8-inch in diameter - on large vessels, generally used for the trunk or backbone cabling with Micro drops to the various devices. Recall that N2K includes two five-pin connector sizes, generally called Mini and Micro and perhaps best seen on this Maretron page. But on a happier note, I’m pretty sure that the eBay purchases above constitute a small, high quality NMEA 2000 network at a bargain price. It turns out that there are many forms of DeviceNet, and several of them are useless for N2K.
![nmea 2000 network cable nmea 2000 network cable](https://www.francis-fustier.fr/blog/wp-content/uploads/NMEA/Schema_Micro-C.jpg)
The cable and connector standard adopted for NMEA 2000 is a subset of the DeviceNet standard used in industrial automation, and if you try to equip your boat with used or surplus DeviceNet gear found online, the term “subset” will take on new meaning.