CAN vs. PWM

So what did you use this year for motor controllers (i.e. Victors, Jaguars, and/or Talons): CAN, PWM, or another system? We used PWM because we have had a lot of issues with CAN in the past, and also because Talons are WONDERFUL!

Can is a little finicky, but it has been reliable for us. You just gotta know its limitations. We run our shooter on V rather than V bus. It has been consistent. It can only be done on Can.

PWM works on all of the legal controllers.

CAN only works on the jaguar.

We stay away from CAN because of its many reliability issues. Additionally, Talons are much, much better motor controllers in so many ways than Jaguars, and Talons don’t have CAN.

Team 957 used PWM witth Talons for reliability and performance.

If it were not for our rookie programming team, we would not have been afraid to utilize CAN with the new IFI Jaguars if we had any use for the functionality. However, we did not find any use for the extra functionality this year.

Last year’s bot utilizes both PWM and CAN, but CAN was not implemented until offseason.

Team 701 made the decision to use Jaguars and CAN when it was first released. We had continuous problems with PWM controls. PWM cables are unreliable, constantly coming loose or falling out completely. PWM cables are not positive locking or keyed.

CAN connections are keyed and positive locking. The connections are reliable and seldom come loose or fall out.

Most of the wiring problems with CAN (and we had many as well) are related to incorrectly manufactured cables. We made our own early on because there were no manufactured cables available. We now have the knowledge and ability to create cables properly.

The additional capability of CAN is hard to pass up. Each Jaguar contains a ARM processor with an enormous amount of functionality. A Jaguar can return the current being used by the motor. This can be used for advanced capabilities like automatic shifting or stall detection. CAN also includes built-in limit switch capability, that can also be queried from the CAN bus. We have used the limit switch interface successfully for several years.

We are sold on CAN and plan to continue using CAN as long as it is available.

Our team has only used PWM twice. Once in our rookie year (2008) and once this season. The reason we switched this year was because we have had many problems with jags over the last few years and PWM is easier to work with. When you buy the right parts to make the cables (and make the cables properly) they will not fall out unless the cable is too short or something goes really wrong. CAN does have the advantage of keyed connectors, but it isn’t hard to remember that the white wire faces out on a victor.