CAN Bus connector? - Page 1
Forum section: electronics / projects

author: jwhitmore
author_rank: Regular Contributor
timestamp: November 05, 2016, 12:38:21 pm
content: I like the three pin JST connector used by Remote Control kit as it's got the power connector in the middle of three connectors so you can't blow anything, worst you can do is connect the signal line to ground. That assumes you connect three pins to the three pins.I'm working on a CAN Bus project and decided that following on from that method I could get a five pin connector, there's a melee of them on ebay , and always have 12V power in the middle, CAN-H and CAN-L on either side of the central power and the two outer connections just being ground.My problem is that that don't lend itself to being a bus connector where you want to take spurs off the bus. The only way to do that would be to put two wires into each crimp connector, which don't seem ideal to me. So how or is there a specific connector for taking off spurs from a bus type arrangement?I'd really appreciate any ideas.http://www.ebay.co.uk/itm/Wholesale-Kits-Car-Boat-Electrical-Waterproof-Connector-1-2-3-4-5-6-Pin-Way-Seal-/152003634379?var=451198652721&hash=item23641f64cb:m:mmFO_nnJkIsvkDF0g1Fgz7w

author: Yansi
author_rank: Super Contributor
timestamp: November 05, 2016, 12:49:23 pm
content: Spurs? what? You meant probably stub. I don't quite get what you are asking for. JST-XH series connectors are quite good and can be sourced easily in whatever you want pin counts. So if you need a CAN and supply voltage, grab a 8 pin connector if you do not wanna crimp two wires in one pin (which I also do not recommend doing). For example: Supply +12V, Supply GND, 1-CANH, 1-CANL, 1-GND, 2-CANH, 2-CANL, 2-GND.But I would strongly recommend to use separate connectors for supply and the CAN bus.Note that if the connector will be disconnected, the bus will be divided in two (so there is this disadvantage of not crimping the two wires together).If you want the Tyco connector, you are limited with pin nubers. You can use also separate connector for CAN and supply then.

author: Rerouter
author_rank: Super Contributor
timestamp: November 05, 2016, 12:51:39 pm
content: use a keyed 4 pin connector? i mean even the connector you show is keyed to the fact you would need to break tabs, cut bits away and force it significantly to plug the thing in backwards...also remeber canbus doesnt work backwards, so in your idea it would be a 7 pin plug,The normal connector set used by buses is the 3 pin duetch connector for Can and signal ground, and then a 2 pin version of the plug you linked for power,

author: jwhitmore
author_rank: Regular Contributor
timestamp: November 05, 2016, 12:59:04 pm
content: Thanks for your replies. I assume when you say that CAN Bus don't work backwards you mean that you can't connect CAN High to CAN Low and expect it to work. ;-) I understand and hope that's what you meat as anything else is going to be news to me.What I mean by a spur, sorry wrong word, anyhow html will mash this but the best I can do is:----------|---------|------------|-----------|-------------|----------I'd like to be able to disconnect "nodes" without effecting the bus at all. It'd still be a functioning CAN Bus.

author: Rerouter
author_rank: Super Contributor
timestamp: November 05, 2016, 01:03:48 pm
content: I'm going to assume J1939 Canbus, ok, so for this protocol, aslong as you keep all stubs short and to the same / similar length, you will be ok, just remember at the ends of the canbus you will need the termination resistors, not at each device, but at the ends,

author: Yansi
author_rank: Super Contributor
timestamp: November 05, 2016, 01:04:16 pm
content: The short paths that goes from the line to the node are called STUBs.You will also likely more disrupt the CAN bus with improper bit timing settings and imprecise clock, than you will do by creating small stubs.

author: nali
author_rank: Frequent Contributor
timestamp: November 05, 2016, 01:46:37 pm
content: You might want to look at NMEA 2000 which is based on CAN and has tee connectors available:http://www.molex.com/molex/products/family?key=nmea_2000_cables_and_connectorshttp://www.ebay.co.uk/itm/Simrad-N2K-garmin-NMEA-2000-T-Connector-2-female-1-male-connector-/201690731304?_trksid=p2141725.m3641.l6368

author: jwhitmore
author_rank: Regular Contributor
timestamp: November 05, 2016, 06:11:48 pm
content: I've seen NMEA connectors in the past, which include power and ground in the connection, but I consider them to be expensive, for the functionality that they provide. They are however the best solution I've seen. Some people have stated that carrying power in the same line is not good, but that's what NMEA seems to do.I also wonder at people's insistence that stubs should be short and similar lengths. I've worked on boats which use  and had very different stub lengths, off that central brake off piece.I'll mull over the NMEA 2000 kit as it does appear to be the best on offer, but for a 5 pin connector it's a bit pricey.http://www.ebay.co.uk/itm/Lowrance-N2K-NMEA-2000-Low-Loss-4-Way-Joiner-000-12612-001-/371760117219?hash=item568ea135e3:g:iEYAAOSwGW9XPdy9