General points on connecting external inputs
The automotive environment is electrically very noisy and without care the signals that you log will also be noisy. There are a couple of things that you can do to reduce this noise to a minimum. Firstly don't run long lengths of wire around the car, if you do need to run a long length of cable then use "shielded twisted pair" cable and use the other cable to connect to earth at the logger and on the sensor.
All the DL# units are equipped with high impedance inputs, meaning they be connected to most analogue inputs without causing a problem. The input impedance of all the inputs is over 100kohm.
There are literally 1000's of sensors that can be used with the DL# units, as long as they output a few volts then they can normally be used. Sensors that output current (5-20mA loop for example) are not suitable for direction connection. Sensors with very low outputs for example thermocouples are also unsuitable for direct connection. If you require advice on supplying or connecting sensors then please contact Race Technology.