A copedent very simply is just what the setup is of the pedals and knee levers and what is the role that each of those does. This guitar is set up in a very common, typical setup, and in this case, my copedent involves three pedals, which is very, very common for this type of guitar, and five knee levers. So in this case, the copedent, we have the A, E, and C pedals, which is a very common setup for the modern iteration. The A pedal raises the B strings a whole step. The B pedal will raise the G Sharp strings a half step. Now, when you're playing an E chord, if both of those things happen at the same time, which is a lot in pedal steel playing, you're going to get suddenly an A chord.
The third pedal raises the E string and the B string a whole step. You can use it alone, but it's most commonly used with the B pedal to make a minor chord. If you're on the G fret and you use the B and C pedals, you get an A Minor chord. You also hear it a lot in this kind of lick. Okay, so that's it for the pedals.
Now, the knee levers do a bunch of different stuff. A very common setup is the left knee lever going left will raise your E's a half step. Likewise, the left knee going right is going to lower the E's a half step. The right knee going left is a tricky one. It does many things. It lowers the sixth string a whole step, and on my guitar, it raises the first string a whole step and the second string a half step. You've got this kind of unusual thing where that goes up and that goes down. Luckily, for obvious reasons, you don't use these very often together. There are cases of adding another knee lever further in to separate those functions so that you can have more flexibility in terms of what you're doing.
Finally, the very last lever, the right going right, will lower your second string a half step. And then you feel that it's joining the ninth string in the unison, and then, as a special bonus, they will both go down yet another half step. You get your seventh by lowering the half step here. That's an E seventh chord, and if you lower it just a little more, that's going to be your sixth. Likewise, this lower D string gets lowered to C Sharp also.
That's basically it for the copendent, a very common, universal copendent for an E ninth chromatic pedal steel guitar.