Maximum PWM length

mechanicalbrain · #1 20-02-2006, 02:03

What is the maximum length you can run a PWM cable without loosing the signal? We are looking at running some sensors and servoss with cables maybe 3 or 5 feet in length, and I want to make sure the signal will make it.

Al Skierkiewicz · #2 20-02-2006, 07:16

That should be no problem.

Josh Hambright · #3 20-02-2006, 07:27

I agree with Al that you should be alright, but i swear i remember reading in something IFI wrote (i dont remember if it was in their forums or in a whitepaper or a datasheet or what) that they said that PWM wires should not be longer then 5 feet.

If i can find the exact document i will edit this and link it.

ECarlson · #4 13-03-2006, 23:06

The only issue with length should be signal interference. In 2002, we designed a remote "runner" mouse for our robot, and it had about 30 feet of cable running to it, with power for a motor, and a signal cable for a steering servo. With the long cables running right next to each other, the motor power cable would interfere badly with the steering of the servo, so we switched to shielded cable for the servo, and it worked fine.

Here's one of the photos of the runner.

mechanicalbrain · #5 13-03-2006, 23:14

Quote:

Originally Posted by ECarlson

The only issue with length should be signal interference. In 2002, we designed a remote "runner" mouse for our robot, and it had about 30 feet of cable running to it, with power for a motor, and a signal cable for a steering servo. With the long cables running right next to each other, the motor power cable would interfere badly with the steering of the servo, so we switched to shielded cable for the servo, and it worked fine.

Here's one of the photos of the runner.

Thats pretty cool but I think I would be afraid to put something like that out on the field. Well ultimately I had no trouble with pwm length. Thanks all.

ECarlson · #6 13-03-2006, 23:18

Quote:

Originally Posted by mechanicalbrain

Thats pretty cool but I think I would be afraid to put something like that out on the field. Well ultimately I had no trouble with pwm length. Thanks all.

It didn't make it out on the field much, but that was a year that lots of teams had runners.

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