CAN - reading current values

Hi all,

Question regarding black jags with CAN;
Without using current control mode, (want to stick with voltage control), can we still access information about the current going through each of our jags, and display them on the dashboard?

Also, in regard to the ‘Jaguar Communication Cables’ section in MDL-BDC24_GSG.pdf (from luminary micro’s jaguar page):
-can the mentioned (6wire) A2662R-07-ND be used (without modification) between the jags, and between the crio and jag?
-are the steps (at the bottom of page 30) to be done to the modular RJ12-DB-9 abapter AND for the terminator plug (both with 100ohm resitors)?

thanks.

You can get the current information in any mode, though it is only accurate within an Amp.

Regular RJ12 cables, like the one you’ve linked to, can be used to connect the Jags and the cRIO together. Between the Jags you actually only need the center two conductors, but I would recommend making all your cables with 6 conductors so you can swap cables around if you need to.

I’m assuming the document you’re referring to is the Getting Started Guide. Yes, you need a termination resistor on both ends of the network. You can use a 100 ohm or a 120 ohm resistor. Make sure to build it in a way that the leads of the resistor will not short together.
Granted, I have gotten CAN to work with only one termination resistor. However, the CAN spec calls for two, so I would use two. You do not want to introduce additional points of failure into the system.

thanks allot Marshal! very detailed and in depth, much appeciated!

another quick question(s) if thats alright, (below part #'s are from digikey)
I’ll be using A2662R-07-ND cable.
which of the following connectors should i get?
A9093-ND
A9117-ND
I’m thinking the latter, as the cable type is “CONN MOD PLUG 6-6 FLAT OVAL AU”, just as described in the “Getting started” guide (except ofc, it was 6-4 in the guide), but i’m not really sure the difference.

and lastly, to your best judgement, would both of the crimpers below be suitable?
digikey: PA1344-ND
http://www.thesource.ca/estore/product.aspx?language=en-CA&catalog=Online&category=Crimping_Tools&product=2798522

thanks very much!

The official CAN spec requires a 120 ohm resistor. However, as seen in the Jaguar documentation, we recommend using a 100 ohm resistor as the terminator on both ends. This is to improve the network reliability when there are many nodes and extra-long cable lengths.

Yes, you should use the plug that is designed for flat cable. Round cable is also usable, but from my experience it is easier to use flat cable because once the outer insulation is stripped, you can just slide it into the plug and crimp it.

Either of the crimpers will be fine. You get 3 features in one for the cheaper crimper, but the more expensive one will probably last longer. Your choice. I use a crimper that resembles the cheap one and I have crimped at least 5 robots worth of modular jacks with no problems.

Be sure to pay close attention to pre-made and homemade cables:

Cables must be ‘straight-pinned,’ which means Pin 1 > 1, Pin 2 > 2, and so on. This is also referred to as a reverse-cable because the tabs on the connectors are on the opposite sides of the cable.

(Taken from the getting started guide)

-David

Can anyone provide a link to the “Getting Started Guide” for CAN/Jaguar as mentioned earlier in this thread?

For the life of me, I cannot seem to find it online anymore.

Thank you in advance!

EDIT:
5 minutes of research led me to
http://www.luminarymicro.com/jaguar