KAGRA/Subgroups/VIS/OpsManual/FishingRods

This page describes the status of the fishing rods and provides characterization information measured at the time of assembly.

It's important to bear in mind that the reported range of the stepper motor in number of steps is not expected to be accurate and it's useful only as a guideline:

Whenever the stepper driver is reset the posion of the motor (measured in number of steps from a zero) is lost and begins counting from zero wherever its physical position is.
Inaccuracies may arise when a stepper motor reaches the physical end of range because the driver still considers valid the requested position even when its beyond the physcal limit.

With respecto to the LVDT range limits, those may change with temperature.

Suspension	Stage	Available	Polarity	Range	Others
ITMX	F0	Stacked[?]
	F1	OK [1]	+Step <-> Up
	F2	OK [1]
	F3	NO [1]
	BF	Stacked[?]
ETMX	F0	?
	F1	?
	F2	?
	F3	?
	BF	?
ITMY	F0	?
	F1	?
	F2	?
	F3	?
	BF	?
ETMY	F0	?
	F1	?
	F2	?
	F3	?
	BF	?

[1] Jul 29 2020, http://klog.icrr.u-tokyo.ac.jp/osl/?r=14820

Contents

Input X
1. F0
2. F1
3. F2
4. F3
5. BF
Ouput X
1. F0
2. F1
3. F2
4. F3
5. BF
Input Y
1. F0
2. F1
3. F2
4. F3
5. BF
Output Y
1. F0
2. F1
3. F2
4. F3
5. BF
Beam splitter
SR2
SR3
SRM

Input X

F0

Range:
- LVDT:
- Stepper motor:
- Temperature when measured:
Observations:

F1

Range:
- LVDT:
- Stepper motor:
- Temperature when measured:
Observations:

F2

Range:
- LVDT:
- Stepper motor:
- Temperature when measured:
Observations:

F3

Not working via medm screen as of Jul 29 2020. (klog#14820)

Range:
- LVDT:
- Stepper motor:
- Temperature when measured:
Observations:

BF

Range:
- LVDT:
- Stepper motor:
- Temperature when measured:
Observations:

Ouput X

F0

Range:
- LVDT:
- Stepper motor:
- Temperature when measured:
Observations:

F1

Range:
- LVDT:
- Stepper motor:
- Temperature when measured:
Observations:

F2

Range:
- LVDT:
- Stepper motor:
- Temperature when measured:
Observations:

F3

Range:
- LVDT:
- Stepper motor:
- Temperature when measured:
Observations:

BF

Range:
- LVDT:
- Stepper motor:
- Temperature when measured:
Observations:

Input Y

F0

Range:
- LVDT:
- Stepper motor:
- Temperature when measured:
Observations:

F1

Range:
- LVDT:
- Stepper motor:
- Temperature when measured:
Observations:

F2

Range:
- LVDT:
- Stepper motor:
- Temperature when measured:
Observations:

F3

Range:
- LVDT:
- Stepper motor:
- Temperature when measured:
Observations:

BF

Range:
- LVDT:
- Stepper motor:
- Temperature when measured:
Observations:

Output Y

F0

Range:
- LVDT:
- Stepper motor:
- Temperature when measured:
Observations:

F1

Range:
- LVDT:
- Stepper motor:
- Temperature when measured:
Observations:

F2

Range:
- LVDT:
- Stepper motor:
- Temperature when measured:
Observations:

F3

Range:
- LVDT:
- Stepper motor:
- Temperature when measured:
Observations:

BF

Range:
- LVDT:
- Stepper motor:
- Temperature when measured:
Observations:

Beam splitter

Top filter

Range:
- LVDT: [ -2500 , +4900 ] µm (7694).
- Stepper motor: [ -1,400,000 , +1,400,000 ] steps (7694).
- Temperature when measured:
Observations:
- At 25 ºC it was possible to use the fishing rod to set the keystone at nominal position (8125).
- at 24.5 ºC or colder it was not (8645, 11465).

Standard Filter

Range:
- LVDT: [ -700 , +700 ] µm (3558).
- Stepper motor: [ -870,000 to +835,000 ] steps (3558).
- Temperature when measured:
Observations:
- It's been at its lowest position since the temperature was 25 ºC (8125, 8645).
- We set the keystone to 488 µm and couldn't move it further down (8125, 8645).

Bottom filter

Range:
- LVDT: [ -1000 µm , +1800 ] µm (3280).
- Stepper motor: [ -746,000 , +746,000 ] steps (3280).
- Temperature when measured:
Observations: this fishing rod doesn't seem to have any problems, but we haven't used it at every temperature condition we've had.

SR2

Top filter

Range:
- LVDT: [ -990 , 903 ] µm (8082).
- Stepper motor: [ -1,700,000 , 1,500,000 ] steps (8082).
- Temperature when measured:
Observations: This fishing rod is not known to have problems. See klog entry 13930.

Stardard filter

Range:
- LVDT: [ -750 , 1000 ] µm (4431).
- Stepper motor: [ 300,000 , 1,000,00 ] steps (4431).
- Temperature when measured:
Observations: This fishing rod is not known to have problems. See klog entry 13930.

Bottom filter

Range:
- LVDT: [ -500 , 600 ] µm (4430).
- Stepper motor: [ -550,000 , -250,000 ] steps (4430).
- Temperature when measured:
Observations: This fishing rod is not known to have problems.

Other related entries

Calculated temperature correction: 8082.
Recovery after pump down: 8160.

SR3

Top filter

Range:
- LVDT: [ 885 , -1299 ] µm (7758).
- Stepper motor: [ -500,000 , 1,100,000 ] steps (7758).
- Temperature when measured:
Observations: After pump down it was not possible to move the keystone to zero using the fishing rod. It went as high as -750 µm at the time (8135).

Standard Flter

Range:
- LVDT: [ -2000 , 2000 ] µm (4720).
- Stepper motor: [ -700,000 , 1,100,000 ] steps (4720).
- Temperature when measured:
Observations:This fishing rod of not working at all (8135). It's a real shame because it had a large range of 4 mm total.

Bottom Filter

Range:
- LVDT: [ -1600 , +1000 ] µm (4654).
- Stepper motor: [ -200,000 , 250,000 ] steps (4654).
- Temperature when measured:
Observations:
- After pump down it was not possible to move the keystone to zero using the fishing rod. It went as high as -265 µm at the time 8658.
- The number of steps for the stepper motor seem relatively small. In principle there's nothing wrong with this but let's point this out.

Other related entries

8658, 8135.

SRM

Top Filter

Range:
- LVDT: [ -865 , 626 ] µm (7857).
- Stepper motor: [ -1,600,000 , 1,600,00 ] steps (7857).
- Temperature when measured:
Observations: This fishing rod is not known to have problems.

Standard Filter

Range:
- LVDT: [ -1,700 , 1,400 ] µm (4721) .
- Stepper motor: [ -700,000 , 1,100,000 ] steps (4721) .
- Temperature when measured:
Observations: This fishing rod is not known to have problems.

Bottom Filter

Range:
- LVDT: [ -3,000 , 2,800 ] µm (4721).
- Stepper motor: [ -600,000 , 800,000 ] steps (4721).
- Temperature when measured:
Observations: This fishing rod is not known to have problems.

Related entries

Recovery after pump down: 8197.