Set Jaguar device number via cRIO

[kamocat]

Buy the cable? It's just a female RJ25 connected to a female DB9. Is the digikey part specially shielded? I don't have shielding over any of my CAN bus.

I tried to find a periodic signal on the CAN bus (the heartbeat), but I couldn't find anything that would qualify for much more than periodic noise. (only a couple of microvolts, really noisy, and extremely unreliable. However, it didn't seem to appear when I didn't have bdc-comm running or I didn't have my hand resting on my computer, if that makes any difference )

[Radical Pi]

Perhaps you aren't using a proper wire. A standard 6-pin cable most likely won't work for the same reason you need a crossover cable. A standard phone wire will swap the conductors and not work with CAN.

[biojae]

Originally Posted by kamocat

Buy the cable? It's just a female RJ25 connected to a female DB9. Is the digikey part specially shielded? I don't have shielding over any of my CAN bus.

No, there is no shielding in the digikey adapter.

It seems that in other adapters (maybe only the ones I bought), that the spacing between the side of the adapter and the pins was slightly off.
The slot was large enough to allow the 6 pin cord to fit in and latch, but the off spacing would make the pins not line up causing no comms in either direction.

Try a continuity test between the pins of the 6 pin cord and the cords inside the adapter (or the DB9 pins).

[taichichuan]

Watch out for the 100 Ohm resistor legs if you tried to put the resistor into the 6P6C connector itself. I experienced many problems with the resistor shorting itself out if I tried building it like the manual says. I found that connecting the resistor to a wire pigtail coming out of the modular connector to be much more reliable.

HTH,

Mike

[biojae]

Originally Posted by taichichuan

Watch out for the 100 Ohm resistor legs if you tried to put the resistor into the 6P6C connector itself. I experienced many problems with the resistor shorting itself out if I tried building it like the manual says. I found that connecting the resistor to a wire pigtail coming out of the modular connector to be much more reliable.

HTH,

Mike

There is nothing a little epoxy can't fix!

After crimping the resistor into the connector (and verifying that it works), take a little 2 part epoxy mixed well and cover the resistor and its legs.

Once it is cured, the resistor won't be able move and the legs will not short each other out.

[kamocat]

Originally Posted by biojae

It seems that in other adapters. the spacing between the side of the adapter and the pins was slightly off.
The slot was large enough to allow the 6 pin cord to fit in and latch, but the off spacing would make the pins not line up causing no comms in either direction.

Try a continuity test between the pins of the 6 pin cord and the cords inside the adapter (or the DB9 pins).

Yes, it seems fine. Less than 0.5 ohms per wire. (The leads on my meter are about 0.2 ohms)
I also double-checked my wires, and they are straight-through.
I've tried the terminating resistor both with and without a pigtail. I think with the pigtail is both more reliable, and easier to create.

[kamocat]

Could somebody unplug their termination resistor, and try enumeration (with the cRIO or the BDC-COMM utility)?
Does it say there's no no devices on the network at all, or does it say there's one device with a device number of 0?

[biojae]

Originally Posted by kamocat

Could somebody unplug their termination resistor, and try enumeration (with the cRIO or the BDC-COMM utility)?
Does it say there's no no devices on the network at all, or does it say there's one device with a device number of 0?

Neither.

I can still enumerate all 4 devices on the CAN bus.

[kamocat]

Is that with a single termination resistor, or with none whatsoever?

[biojae]

Originally Posted by kamocat

Is that with a single termination resistor, or with none whatsoever?

Single termination (one inside the db9 to 6p-6c adapter)

[kamocat]

Okay. The Getting Started guide said small networks may still work with a single termination. I'm not going to ask you to clip off your resistor.

[biojae]

Originally Posted by kamocat

Okay. The Getting Started guide said small networks may still work with a single termination. I'm not going to ask you to clip off your resistor.

I would do it if I had a second (or third) working adapter.
But, the only adapter that I have gotten to work is the digikey one, and we only ordered one of them.

[EricVanWyk]

Originally Posted by kamocat

Okay. The Getting Started guide said small networks may still work with a single termination. I'm not going to ask you to clip off your resistor.

The problem with digital communication is that it works perfectly until it doesn't -- Stating that something works is poor proof that it will continue to work after something changes. You really want to look at the signal in analog land before making these determinations.

It is quite possible / easy to get small CAN networks to work with poor bus layout / terminations.

[kamocat]

I think if the enumeration worked, then the other CAN communications would work. However, I don't know what would cause the enumeration to respond like this.
What does it mean when it says there's only one device on the network, and its address is 0? Why doesn't it just say there are no devices there?

[rrossbach]

Sorry if this is a dumb question, but I'm not clear on what behavior you're seeing.

How many Jaguars do you have connected to the CAN bus? If it's only one, and you are just seeing an enum response with device id 0, have you tried resetting the id of that Jag to something >=2 via bdc-comm? If not, follow the steps on page 10 of the bdc-comm user's guide and let us know the results.

If you still have multiple Jags on the CAN bus, let us know what you see in bdc-comm.....do you see all the Jags except the one with device id 0?

You may just need to assign a new id to the Jaguar that currently thinks it is id 0.

- Ron
Team #2607 controls mentor

[EDIT: to answer your question, the enum responding that there's one device with id 0 is (I'm almost positive) a valid response, provided that's the actual situation on the CAN bus]