Can you afford to lose position in case of power failure? If the answer is no, then you must use an absolute encoder. An incre-mental encoder simply generates pulses proportional to the position, whereas an absolute encoder generates a unique code for each position. After a power outage, with an absolute encoder the machine operation will pick up from where it had left off. In an incremental encoder the pulses generated are counted in a counter and at power loss it will lose the count and consequently you will have to home the machine before you can start the operation. Also, an incremental encoder is generally more susceptible to electrical noise. The absolute encoders are more expensive than the incremental encoders are.

Therefore, a price/feature trade-off may be worth considering.