pwm question

[flamefixed]

first and foremost..excuse my lack of knowledge and proper vocab when it comes to this thread. im a fab-er and driver and team captain (hence why im asking this), though i have picked up a decent knowledge to at least make an attempt to make sense haha.

that said, heres the question: we may be using two CIMs to power the gearbox we built to move the "guillotine" we call it (telescoping lift). the way its built, it needs to be very precise in the movement of the motors if we do use two (nylon gears, not my decision, but we were told by BASF engineers they are plenty strong for our application). i read in the rules that each motor must be connected to a pmw? (this is where my knowledge of specific names is not up to par)

so this means both motors cannot be controlled by one pwm? making both motors move electrically as one (one motor just opposite direction)?

will using two still guarantee that the motors move in exact unison with one another? any tips and tricks?

thanks in advance for any help and please ask questions if i just made no sense whatsoever and ill try my best to clarify
-stevo

[Matt C]

Each CIM motor must be connected to a speed controller (Victor 884). You can split the PWM output with a Y cable included in the KOP (yellow black and red rather than white black and red). This allows you to connect 2 speed controllers to the same RC output.

[SgtMillhouse648]

The way it will work, is the CIMS will each be wired to the Victor 884 speed controllers. From the Speed Controllers, a PWM cable is run to the main controller. You can in the code, drive the motors at the same speed (PWM value), but due to there being two motors, they will never run at the same exact speed. Any two motors, even being the same model, will run at slightly different speeds due to differences in their contruction. As for precise, if you mean run at the same speed (which I think you mean), you shouldn't have too much problem. They should be close enough to not cause any major problems. An example is the twin CIM gear boxes that many teams use. As for turning the same amount and stopping the motors at a given angle, that's a different story, but it can be done.
Good Luck
Malhon

[mtaman02]

Each CIM Motor must have its own Speed Controller (Victor 884) and you can either use the Y-PWM Cable going from the 2 Speed Controllers and use one PWM Channel output on the RC or use 2 seperate PWM Cables and PWM Channel outputs on the RC.

[flamefixed]

thanks everyone. you not only answered my question entirely, it helped educate me further with all this. :]