Calibrating Victors

[Al Skierkiewicz]

Yes, you are all right except for one thing. If you are not absolutely sure that your RC outputs full range PWM for full motion on your joysticks then your systems are faulty. Whether you correct that flaw in software or if you correct it by calibration does not matter as long as you get full range. At extremes several conditions (of thousands) can exist without calibration...
1. Joysticks analog output is converted to a range of 50- 205 for full travel.
2. Joystick's analog output is converted to the range 0-255 for only 60% of it's travel.
3. Joystick's analog output is converted to the range 0-200 for full travel.

If you know for certain that pulling back on the joystick will always output 0 at it's limit and pushing forward will always output 255 at it's limit then you do not need to calibrate. For any other condition, calibrating the controller will insure your full range. As Ken indicated, the LED on the controller will tell you if you have achieved full range but it will not indicate if you achieved it with symmetrical motion, full travel, or software intervention or simply that you were lucky enough to get a set of joysticks that output an analog voltage that perfectly matches the ADC in the RC.
I am not saying you are wrong for not calibrating, just that you are not sure you are capable of full range and matched output charachteristics for all drive motors. More often than not, robots that can't drive straight or stable do not have matched drive signals, particularly for tank style driving and multi motor systems.
I would like to add that I think the IFI guys are very smart and doing a great job with these control systems. They gave us the calibration procedure at some production cost (per unit) because they thought it was needed. They knew what variables exist in the system and they allow us to compensate for them in software or hardware as we see fit.