Soak the cedar plank, fully submerged in water, for 30 minutes. Pat dry after removing from water.
Prepare grill for indirect cooking.
Combine dry rub ingredients in a small bowl.
Coat salmon with olive oil, and then sprinkle about 2 tablespoons of the dry rub over the salmon liberally (you may have some dry rub leftover).
Place seasoned salmon on the cedar plank, and place on direct heat for up to 15 minutes or until the salmon reaches an internal temperature of 120 degrees. While the salmon is cooking, place the lemon half over direct heat and cook 4-5 minutes, until char marks appear.
Transfer the salmon and cedar plank to indirect heat, and glaze with the maple syrup using a brush, and continue cooking until the internal temperature reaches 130 degrees. Remove from the grill. Carry over cooking will continue cooking the salmon to 135 degrees.
Let rest for five minutes and then slice and serve. If using the grilled lemon, squeeze some of the grilled lemon over the top when serving.