Quote:
Originally Posted by Kodiak
Ha, how can the wire be too long? on such a short distance with data flying at 1mbs and the Jaguars acting as switches. Also I would like your input on this, for Joystick input, would it be best on Periodic or Continuous?
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Quote:
Originally Posted by Kodiak
I guess it can be looked at it just like in Networking, but what I think they may mean about being too long is the distance of wire used between one Jaguar to the next and maybe not meant in total distance, which sounds the same but its not, lol.
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Bryscus is correct:
Quote:
Originally Posted by Bryscus
It possibly has to do with loading down the CAN cable driver. I think the total cable length is something like 20' if I remember right. One suggestion was to buy a 20' cable and use it. If you need more, you've used too much.
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It is in fact 20' total,
not the maximum between each Jaguar. The Jaguars aren't switches or repeaters, the left and right CAN ports are wired directly to each other on the Jaguar circuit board.
This 20' limitation does have to do with the CAN driver:
When all the Jaguars are responding at the same time to broadcast messages they drive the bus slightly higher than a single Jag would. It takes longer for the bus to return to 'zero' and therefor some Jaguars may not read the bit correctly if the bit hasn't had time to settle.
The time from high to low depends on the termination resistance as well. This is the reason why we also specify a 100 ohm termination resistor. It helps snap the bus back to zero quickly so there aren't any bit timing errors.
We found that 20' of cable, 100 ohm termination resistors, and ~16 Jags on a bus is a good limit for reliable operation. It may be possible to get more Jags, but the cable lengths will have to be shorter.
-David