NCAL Update -- First Signal in DARM!

[Jeff Kissel, Filiberto Clara, Patrick Thomas, NCAL Team, Timesh Mistry, Krishna Venkateswara (in spirit)]

We spun the Newtonian Calibrator Prototype and observed the first NCAL signal in DARM!

Initially, we werre still having power issues however, Fil noticed that the negative cable for the AC power was not connected correctly and fixed the issue. Once completed, there were no more power errors and we were able to activate the motor using the MEDM screen. As part of Fil's fix, we now have a DC power supply that is running next to the Beckhoff rack where the motor controller is installed (same place as the BRS Beckhoff rack). This power supply will remain powered after we leave the X-End and may cause some exess noise at the X end. This will be rectified next Tueday maintenace as well as tiding up the remaning NCAL wiring.

We drove the NCAL at two frequencies (6.14Hz and 6.34Hz) using the MEDM/EPICS interface and, at each frequency we used PCALY to drive lines close to NCAL 2f and 3f lines. We chose PCALY becuase we wanted to have an isolated reference line near the NCAL line (recall the NCAL is at the X end). We kept and eye on the PCALY to ensure we were not saturating the PCAL as well as monitering the power supply at the X end to ensure we were not drawing too much current. Thoughout the tests, we did not saturate the PCAL or trip the power supply.

NCAL at 6.14Hz without PCALY
NCAL at 6.14Hz with PCALY
NCAL at 6.34Hz with PCALY
NCAL at 6.34Hz without PCALY

The dotted blue lines show the 2f and 3f NCAL signals respectivetly. It is interesting that we do not see the any higher order harmonics, such as 4f, 5f, 6f etc. It is currenlty inknown the impact the NCAL is having in other auxhillary channels and this will be investigated further.

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Time Log of X End Activities

13:42:15

The velolcity counts to the NCAL motor is 644 counts. Motor start spinning, the NCAL signals are as follows:

NCAL Harmonic	Expected Frequency (Hz)
1f	6.14
2f	12.28
3f	18.42

13:46:00

NCAL reached the requested frequency.

13:52:20

PCALY lines are enabled and configured to have a line close to the 2f and 3F NCAL signal.

PCALY Frequency (Hz)	PCALY Counts
12.17	100
18.51	100

14:00:00

Switched NCAL frequency to 655 counts.

NCAL Harmonic	NCAL Frequency
1f	6.3419
2f	12.683
3f	19.025

14:00:20

New frequency reached.

14:01:40

PCAL lines switched to new frequency.

PCALY Frequency	PCALY counts
12.61	100
18.83	100

14:15:00

PCALY lines turned off. NCAL remains at 655 counts.

14:30:00

NCAL set to 0 counts.

14:31:07

NCAL is at rest verified using traces on the MEDM screen showing 0 for the torque and the motor velocity and there are not more signals in DARM.

14:32:00

Power to the motor is disabled.

14:35:00

Left the X end. Wifi off, Phone unplugged and lights off.