This page is for writing explanations or plans which we are not confident about and may be subject to change. For instance, a possibe course of action to carry out a particular type of measurement or the plan to follow to identify a noise source.It's also for temporary random notes.


This entry is about Type B Guardian

The Guardian manual is here.

controls@k1ctr0:~$ userapps

From herer cd to vis/k1/guardian/

In each Type B suspension we have two nodes. One monitors the tower and another one monitors the payload. Which one controls the master switch?

Each Type B node is a device node that talks directly to hardware.

Each node is a daemon. They load system modules.

The file with the st

Highlights:

Questions:


This entry is about IP LVDT correction with the seimometer signal

ther people have been working in the correction of the IL LVDT using the seismometer signal

Concept

Aim

In order to properly damp the motion of the IP we would like to estimate the motion of the IP table w.r.t. an inertial reference frame. However, we currently don't have an appropriate inertial sensor for this task. The aim of sensor correction is to use the readout of a seismometer on the ground in order to remove the contribution of the ground motion from the IP LVDT readout, which provides the relative displacement of the IP table with respecto to the ground.

Method

Sensor correction requires an estimate of the ground motion in order to remove it from the IP LVDT signal. In reality, what is required is an estimate of the motion of the platform which supports IP at the top of the frame. An infinitely rigid frame the transfer function will be one.

Notes about the seismometer:

Notes about the filters


How to find whaty are DQ channels available

controls@k1ctr3|20190828> ssh k1sum0

controls@k1sum0:~$ conda activate ligo-summary-3.7

(ligo-summary-3.7) controls@k1sum0:~$ FrChannels /frame0/science/12510/K-K1_R-1251005728-32.gwf | grep DQ | more


SR2 GAS filter control

Date: 28-08-2019

Author: Fabian

Context: There's high coherence of the GAS LVDT with the vertical ground motion.

Directory: /kagra/Dropbox/Subsystems/VIS/TypeBData/SR2/Noise/Measurements/20190828/

File: SR2_ALIGNED_TM_OPLEV_ASD_190828.xml

The F0 transfer function measured on the 27th of July were not successful, therefore, I measured again for the sake of health. It tuned to be alright.

Resonant frequencies of the GAS filter transfer functions are:

Oplev control in SR3

Date: 19-08-2019

Author: Fabian

Context: On Friday Enomoto-kun implemented new filters for the SR3 optic local control. See klog entry 10014. The aim is to control lower frequency motion. What frequency?

Noise hunting in SR3 optics' residual motion

Date: 05-08-2019.

Author: Fabian.

Context: entry from 03-08-2019 and klog entries 9702 and 9755.

Following the plan for noise source identification I measured the coherence between the following degrees of freedom:

The highlights for the ALIGNED state are

Date: 03-08-2019.

Author: Fabian.

Context: klog entries 9702 and 9755.

On Friday afternoon I found high coherence between SR3 L and P degrees of freedom in at least two frequency bands, as measured by the oplev. High coherence is observed in both states ALIGNED and FLOAT.

Possible reasons for the high coherence are:

Plan for noise source identification.

Plan for reducing control noise