Apply suggestions from code review

Co-authored-by: Peter Law <[email protected]>
Co-authored-by: Will Barber <[email protected]>

Author: 3 people

programming/sr/motors/index.md

@@ -39,7 +39,9 @@ R.motor_boards["srABC1"].something...
 Setting motor power
 -------------------
 
-Motor power is controlled using [PWM](https://en.wikipedia.org/wiki/Pulse-width_modulation) with 100% power being a [duty cycle](https://en.wikipedia.org/wiki/Duty_cycle) of 1. You set the power with an integer value between -100 and 100 inclusive (where a negative value puts the motor in reverse). The field to change the output power is `power`. As each Motor Board has two outputs you will need to specify which output you want to control:
+Motor power is controlled using [PWM](https://en.wikipedia.org/wiki/Pulse-width_modulation) with 100% power being a [duty cycle](https://en.wikipedia.org/wiki/Duty_cycle) of 1. You set the power with an integer value between -1 and 1 inclusive. Fractional values (such as 0.42) can be used to specify less than 100% power. Negative values run the motor in the opposite direction.
+
+The field to change the output power is `power`. As each Motor Board has two outputs you will need to specify which output you want to control:
 
 ~~~~~ python
 from sr.robot3 import *
@@ -69,7 +71,7 @@ You can read the current power value for a motor using the same field:
 
 ~~~~~ python
 # get the current output power of Motor Board srABC1, channel 0
-currentTarget = R.motor_boards["srABC1"].motors[1].power
+currentTarget = R.motor_boards["srABC1"].motors[0].power
 ~~~~~
 
 Stopping the motors