From 14 to 18 September we installed the SQB1 multiSAS inside its minitower in the detection lab. Before hoisting we shortened the steel lifting cable length by two meters, in order to reduce the number of cable layers on the pulley to maximum 3-4 making the hoisting much more easy.
The electronics boards for the stepper motor drivers, voice coil actuators, geophone and Trillium have been installed and configured. Both sides of each of the signal cables are marked equal corresponding to the names on the breakout box at the North side of the minitower. The Geophone pre amplifier was removed and the sensor temporarily directly connected to the ADC.
Horizontal sensor positioning:
Both the geophone and the F0H0 LVDT are located near the electronics breakout box(north side) and oriented along the Z axis. On the opposite side of the top stage the Trillium is placed, its local north coordinate is pointing towards the +X direction (towards SDB1).
Linearized sensitivities of raw LVDT’s (um/V):
- F0V 240
- F1V 261
- F0H0 344
- F0H1 321
- F0H2 294
Tuning of the MSAS modes:
- IP-Modes horizontal: 45 mHz (X,Z)
- IP-Mode yaw: 370 mHz (Ty) *
- Intermediate filter (IF) tilt: 620 mHz (Tx,Tz)
- IF differential pendulum: 1.67 Hz (X,Z)
- GAS filter F0; 150 mHz (Y)**
- GAS filter F1; 120 mHz (Y)**
(* The remaining (torsion) modes are all below 20 mHz)
(** resulting in common and differential mode of 100 and 700 mHz respectively)
The payload mass equals 324 kg. The IP and intermediate balance mass writes 18.5 and 16.2 kg respectively. The SBE-SQB1 Minitower is closed and the electrical cables have been disconnected for the installation of the cable ducts and the final routing from the crates towards the Minitower. After reconnection we can start to close the control loops and define the initial control settings.
To be done:
- Replace vertical correction springs on the intermediate filter
- Replace geophone/seismometer board