• • Strange behavior in June 2008

• • GDAQ was removed on April 18, 2008 and re-installed the following week. It had a dead RS232 interface chip that converts the serial comm. signals from TTL levels (out of the ADuC834) to real RS232 levels.

• • GDAQ was removed on April 18, 2008 and re-installed on April 22 at 10:42 AM. It had a dead RS232 interface chip that converts the serial comm. signals from TTL levels (out of the ADuC834) to real RS232 levels.

• • Was repaired and reinstalled on 23 July 2007. Not sure when it went bad, but was bad as early as March 27, 2007

• • Was repaired and reinstalled on 23 July 2007. Not sure when it went bad, but was bad as early as March 27, 2007.

• • GDAQ was removed on April 18, 2008 and re-installed the following week. It had a dead RS232 interface chip that converts the serial comm. signals from TTL levels (out of the ADuC834) to real RS232 levels.

-- KimConstantikes - 04 Sep 2003

• • The GDAQ is based on Analog Devices ADuC834 precision analog microcontroller. It uses a sigma-delta modulator which converts the sampled input signal into a digital pulse train whose duty cycle contains the digital information. A sinc^3 programmable low-pass filter is then employed to decimate the modulator output data stream to give a valid data conversion result at programmable output rates from 5.35 to 105.03 Hz. Here is a plot of the measured passband.

• • The GDAQ is based on Analog Devices ADuC834 precision analog microcontroller. It uses a sigma-delta modulator which converts the sampled input signal into a digital pulse train whose duty cycle contains the digital information. A sinc^3 programmable low-pass filter is then employed to decimate the modulator output data stream to give a valid data conversion result at programmable output rates from 5.35 to 105.03 Hz. Here is a plot of the measured passband with no external RC filter. Here is the same measurement with an RC filter of 120kohm and 0.33uF (corner freq = Hz).

• plotsweeprc.pdf: GDAQ response with RC filter of 4Hz on front end

• • Accelerometer pre-processing op-amp card schematic

• • Accelerometer pre-processing op-amp card schematic: original, Cut-and-patch revision 2

%META:FILEATTACHMENT{name="SingleAxisAcelerometerSchematicrevAC_P_2.pdf" attr="" comment="Cut & Patch, #2" date="1203616197" path="Single Axis Acelerometer Schematic revA C_P_2.pdf" size="36260" user="ToddHunter" version="1.1"}%

• • AccelerometerHardwareSignalProcessing prior to ADC (from Jason Ray) (schematic)

• • Accelerometer pre-processing op-amp card schematic
  • AccelerometerHardwareSignalProcessing of X-axis channel prior to ADC (from Jason Ray) (schematic)

%META:FILEATTACHMENT{name="SingleAxisAccelerometerMasterCardSchematicrevADWG.bmp" attr="" comment="Accelerometer pre-processing op-amp card" date="1203554693" path="Single Axis Accelerometer Master Card Schematic revA DWG.bmp" size="3168054" user="ToddHunter" version="1.1"}%

• • The GDAQ is based on Analog Devices ADuC834 precision analog microcontroller. It uses a sigma-delta modulator which converts the sampled input signal into a digital pulse train whose duty cycle contains the digital information. A sinc^3 programmable low-pass filter is then employed to decimate the modulator output data stream to give a valid data conversion result at programmable output rates from 5.35 to 105.03 Hz.

• • The GDAQ is based on Analog Devices ADuC834 precision analog microcontroller. It uses a sigma-delta modulator which converts the sampled input signal into a digital pulse train whose duty cycle contains the digital information. A sinc^3 programmable low-pass filter is then employed to decimate the modulator output data stream to give a valid data conversion result at programmable output rates from 5.35 to 105.03 Hz. Here is a plot of the measured passband.

• • MR describing the Accelerometer manager
  • Routine storage of data in /home/gbtlogs began on 2006_06_28 (2006 June 28)

The data are written into /home/gbtlogs/Accelerometer-AccelerometerX-AccelerometerData (where X=1..4)

• • See timeseries and FFT plots during elevation scan here

• • To be mounted on the optical camera mount near the vertex.

• • Mounted on the optical camera mount near the vertex.

• • See timeseries and FFT plots during elevation scan here

• • The manufacturer and model number is Silicon Designs Model 1221J-002 Low-noise Analog Accelerometer.

• • The manufacturer and model number is Silicon Designs Model 1221J-002 Low-noise Analog Accelerometer. The 3dB bandwidth is 400 Hz, but this is filtered by the sigma-delta conversion on the GDAQ.

• • The GDAQ is based on Analog Devices ADuC834 precision analog microcontroller.
  • The sample rate of each channel is nominally 10 Hz, but in practice show up at about 9.5 Hz in the files in the gbtlogs area.
  • The Y and Z axes are read through the 24 bit ADC and the X is read through the 16 bit ADC (both on board the ADuC834?).

• • The GDAQ is based on Analog Devices ADuC834 precision analog microcontroller. It uses a sigma-delta modulator which converts the sampled input signal into a digital pulse train whose duty cycle contains the digital information. A sinc^3 programmable low-pass filter is then employed to decimate the modulator output data stream to give a valid data conversion result at programmable output rates from 5.35 to 105.03 Hz.
  • The sample rate of each channel is nominally set to 10 Hz, but in practice show up at about 9.5 Hz in the files in the gbtlogs area.
  • The Y and Z axes are read through the 24 bit ADC and the X is read through the 16 bit ADC (both on board the ADuC834).

• • AccelerometerHardwareSignalProcessing prior to ADC (from Jason Ray)

• • AccelerometerHardwareSignalProcessing prior to ADC (from Jason Ray) (schematic)

%META:FILEATTACHMENT{name="2558_001.pdf" attr="" comment="Signal conditioning circuit for X-axis on Aux ADC " date="1198105603" path="2558_001.pdf" size="71311" user="ToddHunter" version="1.1"}%

• • The sample rate of each channel is nominally 10 Hz, but in practice show up at about 9.5 Hz in the files in the gbtlogs area.

• • AccelerometerSignalProcessing prior to writing data to the engineering FITS file.

• • AccelerometerHardwareSignalProcessing prior to ADC (from Jason Ray)
  • AccelerometerSignalProcessing prior to writing data to the engineering FITS file (from Joe Brandt)

• • The accelerometer positive X-axis corresponds to the GBT positive Xe axis.

• • The accelerometer positive X-axis corresponds to the GBT positive Xe axis (see attachment)

• • The accelerometer positive X-axis corresponds to the GBT negative Xa axis.

• • The accelerometer positive X-axis corresponds to the GBT negative Xa axis (see attachment)

• • The Y and Z axes are read through 24 bit ADCs and the X is read through a 16 bit ADC.

• • The Y and Z axes are read through the 24 bit ADC and the X is read through the 16 bit ADC (both on board the ADuC834?).

• • Todd's MATLAB fits to accel. 1 data vs. elev on 2007/12/04

• • cos(elev) fit to y-axis data
  • sin(elev) fit to z-axis data

• • plot of python fits: cos(elev) fit to y-axis data sin(elev) fit to z-axis data

• • Todd's MATLAB fit to accelerometer 4 data vs. elevation

• • Todd's MATLAB fits to accelerometer 4 data vs. elevation

%META:FILEATTACHMENT{name="accel4.gif" attr="" comment="MATLAB fit to accelerometer 4 data vs. elevation" date="1196787009" path="accel4.gif" size="13050" user="ToddHunter" version="1.1"}%

%META:FILEATTACHMENT{name="accel4.gif" attr="" comment="MATLAB fit to accel. 4 data vs. elev on 2007/12/04" date="1196787009" path="accel4.gif" size="13050" user="ToddHunter" version="1.1"}% %META:FILEATTACHMENT{name="accel1.gif" attr="" comment="MATLAB fit to accel. 1 data vs. elev 2007/12/04" date="1196791830" path="accel1.gif" size="12670" user="ToddHunter" version="1.1"}%

• • Todd's MATLAB fit to accelerometer 4 data vs. elevation

%META:FILEATTACHMENT{name="accel4.gif" attr="" comment="MATLAB fit to accelerometer 4 data vs. elevation" date="1196787009" path="accel4.gif" size="13050" user="ToddHunter" version="1.1"}%

• • The accelerometer positive X-axis corresponds to the GBT positive Xe axis.
  • The accelerometer positive Y-axis corresponds to the GBT positive Ye axis.
  • The accelerometer positive Z-axis corresponds to the GBT positive Ze axis.

• AccelerometerFour
  • To be mounted on the optical camera mount near the vertex.
  • Jason's Excel table of calibration data with figure showing orientation definitions

%META:FILEATTACHMENT{name="Accelerometer4checkout-070913.xls" attr="" comment="Jason's Excel table of calibration data for acc#4" date="1194397824" path="Accelerometer 4 checkout-070913.xls" size="16384" user="ToddHunter" version="1.1"}% %META:FILEATTACHMENT{name="AccelOrientations.pdf" attr="" comment="Definition of orientations in calib data for acc#4" date="1194397904" path="AccelOrientations.pdf" size="24356" user="ToddHunter" version="1.1"}%

• • Was repaired and reinstalled on 23 July 2007.

• • Was repaired and reinstalled on 23 July 2007. Not sure when it went bad, but was bad as early as March 27, 2007

• • plot of X,Y,Z outputs during tipping scan
  • fit results for gravity curve of Y and Z axis
  • cos(elev) fit to y-axis data
  • sin(elev) fit to z-axis data

• tipaccel.pdf: accelerometer 1 outputs during tipping scan

• fit.results: fit for gravity curve of Y and Z axis of accel1

• coselfit.pdf: cos(elev) fit to y-axis data

• sinelfit.pdf: sin(elev) fit to z-axis

• tipaccel.pdf: accelerometer 1 outputs during tipping scan

• fit.results: fit for gravity curve of Y and Z axis of accel1

• coselfit.pdf: cos(elev) fit to y-axis data

• sinelfit.pdf: sin(elev) fit to z-axis

%META:FILEATTACHMENT{name="tipaccel.pdf" attr="" comment="accelerometer 1 outputs during tipping scan" date="1193497180" path="tipaccel.pdf" size="92577" user="ToddHunter" version="1.1"}% %META:FILEATTACHMENT{name="fit.results" attr="" comment="fit for gravity curve of Y and Z axis of accel1" date="1193497356" path="fit.results" size="509" user="ToddHunter" version="1.1"}% %META:FILEATTACHMENT{name="coselfit.pdf" attr="" comment="cos(elev) fit to y-axis data" date="1193497388" path="coselfit.pdf" size="57519" user="ToddHunter" version="1.1"}% %META:FILEATTACHMENT{name="sinelfit.pdf" attr="" comment="sin(elev) fit to z-axis" date="1193497414" path="sinelfit.pdf" size="51302" user="ToddHunter" version="1.1"}%

• • Was repaired and reinstalled on 23 July 2007.

• Useful facts noted by Todd

• • The Y and Z axes are read through 24 bit ADCs and the X is read through a 16 bit ADC.
  • The X axis has an intentional offset of +0.625V when horizontal. The other axes are nominally 0.0V when horizontal from what I can surmise.

• The manufacturer and model number is Silicon Designs Model 1221
• The GDAQ is based on Analog Devices ADuC834

• The manufacturer and model number is Silicon Designs Model 1221J-002 Low-noise Analog Accelerometer.
• The interface cards and 3-axis mechanical assembly was created at Green Bank.
• The GDAQ is based on Analog Devices ADuC834 precision analog microcontroller.

• The manufacturer and model number is Silicon Designs Model 1221
• The GDAQ is based on Analog Devices ADuC834
• AccelerometerSignalProcessing prior to writing data to the engineering FITS file.

-- ToddHunter - 11 Jul 2007

%META:FILEATTACHMENT{name="m081-1.pdf" attr="" comment="GBT Coordinate System Drawing" date="1161270414" path="m081-1.pdf" size="106481" user="JohnFord" version="1.1"}%

%META:FILEATTACHMENT{name="m081-1.pdf" attr="" comment="GBT Coordinate System Drawing (page 10 of Memo165)" date="1161270414" path="m081-1.pdf" size="106481" user="JohnFord" version="1.1"}%

%META:TOPICMOVED{by="RichardPrestage" date="1165685344" from="PTCS.StructuralAccelerometers" to="PTCS.AccelerometerSystemDescription"}%

• AccelerometerOne
  • Mounted on the ceiling in the receiver room.
  • Connected to gbtts1, port 2007.
  • The accelerometer positive X-axis corresponds to the GBT positive Xe axis.
  • The accelerometer positive Y-axis corresponds to the GBT negative Ye axis.
  • The accelerometer positive Z-axis corresponds to the GBT negative Ze axis.
• AccelerometerTwo
  • Mounted on the left side EL bearing casting (opposite the elevator)
  • Connected to gbtts6, port 2006.
  • The accelerometer positive X-axis corresponds to the GBT negative Xa axis.
  • The accelerometer positive Y-axis corresponds to the GBT negative Ya axis.
  • The accelerometer positive Z-axis corresponds to the GBT positive Za axis.
• AccelerometerThree?
  • Mounted on the right side EL bearing casting
  • Connected to gbtts6, port 2007.
  • The accelerometer positive X-axis corresponds to the GBT negative Xa axis.
  • The accelerometer positive Y-axis corresponds to the GBT negative Ya axis.
  • The accelerometer positive Z-axis corresponds to the GBT positive Za axis.

%META:FILEATTACHMENT{name="m081-1.pdf" attr="" comment="GBT Coordinate System Drawing" date="1161270414" path="m081-1.pdf" size="106481" user="JohnFord" version="1.1"}% %META:FILEATTACHMENT{name="m081-2.pdf" attr="" comment="Coordinate System Definition, P1" date="1161270522" path="m081-2.pdf" size="103305" user="JohnFord" version="1.1"}% %META:FILEATTACHMENT{name="m081-3.pdf" attr="" comment="Coordinate System Definition, P2" date="1161270614" path="m081-3.pdf" size="70852" user="JohnFord" version="1.1"}% %META:FILEATTACHMENT{name="m081-4.pdf" attr="" comment="Coordinate System Definition, P3" date="1161270647" path="m081-4.pdf" size="80504" user="JohnFord" version="1.1"}% %META:FILEATTACHMENT{name="m081-5.pdf" attr="" comment="Coordinate System Definition, P4" date="1161270677" path="m081-5.pdf" size="67860" user="JohnFord" version="1.1"}%

%META:TOPICINFO{author="KimConstantikes" date="1062705594" format="1.0" version="1.1"}% %META:TOPICPARENT{name="AntennaInstrumentation"}%

• AccelerometerStatusLog

-- KimConstantikes - 04 Sep 2003