40m QIL Cryo_Lab CTN SUS_Lab CAML OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  40m elog  Not logged in ELOG logo
Message ID: 16964     Entry time: Thu Jun 30 17:19:55 2022
Author: Deeksha 
Type: Summary 
Category: Electronics 
Subject: Measured Transfer Functions of the Control Loop, Servo (OLTF); got Vectfit working  

[Cici, Deeksha]

We were able to greatly improve the quality of our readings by changing the parameters in the config file (particularly increasing the integration and settle cycles, as well as gradually increasing our excitation signals' amplitude). Attached are the readings taken from the same (the files directly printed by ssh'ing the SR785 (apologies)) - Attachment 1 depicts the graph w/ 30 data points and attachment 2 depicts the graph with 300 data points. 

Cici successfully vectfit to the data, as included in Attachment 3. (This is the vectfit of the entire control loop's OLTF). There are two main concerns that need to be looked into, firstly, the manner in which to get the poles and zeros to input into the vectfit program. Similarly, the program works best when the option to enforce stable poles is disabled, once again it may be worth looking into how the program works on a deeper level in order to understand how to proceed. 

Just as the servo's individual transfer function was taken, we also came up with a  plan to measure the PZT's individual transfer function (using the MokuLab). The connections for the same have been made and the Moku is at the Xend (disconnected). We may also have to build a highpass filter (similar to the one whose signal enters the PZT) to facilitate taking readings at high frequencies using the Moku. 

Attachment 1: TFSR785_29-06-2022_114042.pdf  19 kB  Uploaded Thu Jun 30 18:24:59 2022  | Show | Hide all | Show all
Attachment 2: TFSR785_29-06-2022_114650.pdf  28 kB  Uploaded Thu Jun 30 18:25:11 2022  | Hide | Hide all | Show all
Attachment 3: TF_OLG_vectfit.png  46 kB  Uploaded Thu Jun 30 18:27:07 2022  | Hide | Hide all | Show all
ELOG V3.1.3-