# Homework Help: Variation of poles

1. Sep 1, 2012

### Ioannis86

1. The problem statement, all variables and given/known data

Hello, I would like your comments on my observations. I have a set of data from a step experiment, one input (volts D.C), one output (temperature). By doing system identification, the resultant model is second order and its poles lie at 0.99 and 0.8 (z-plane)

Now for the set of data, the sampling rate is 5 seconds. What I did is I took the same set of data and made a new one by appending one sample per 10 samples (50 seconds sampling rate). The parameters of the new model give me the poles at 0.92 and 0.65.

In a closed loop system I know that the closer a pole is to zero, it indicates a faster response. Does that also applies for my open loop transfer function?
Physically, from the data, I can understand that by using 50sec sampling rate there is a bigger temperature change at every sample as compared to 5 sec rate.
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution