LawReader Technical consultants announce new  product

 

 

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BILLINGSLEY AEROSPACE & DEFENSE

 20936 Theseus Terrace, Germantown, Maryland 20876

301-540-8338 Phone 301-540-6231 FAX

 sales@billingsleyaerospace.com www.billingsleyaerospace.com

 

New product announcement   (2^nd QTR. 2006)

 

APEX-CS HELMHOLTZ CONTROLLER

 

Precision Magnetic Field Calibration System

Integrated Turnkey Helmholtz Coil Control / Data Collection Controller

with Automatic Self Calibration Capability

 

The controller/data collection platform can be used to upgrade* existing Helmholtz facilities by replacing all of the electronics with this single chassis controller.

 

New technology Helmholtz coil current drivers. The drivers are low power*+ consumption switching type with > 90% energy efficiency. They are ideally suited for use with both our 2.2 meter and 1 meter triaxial Helmholtz coils. They have low noise convection cooling with no fans.

20-bit resolution (0.19 nT) of magnetic field setting with range of ± 1 Gauss (2-3 Gauss special). Closed loop servo amplifiers maintain the set field values stable to < 0.1 nT over extended time periods and < 0.5 nT change in 24 hours at constant ambient temperature.

Triaxial fluxgate magnetometer sense head with optional (4^th) single channel*** precision reference magnetometer for system self calibration. The sense head senses changes in the ambient field (i.e. Earth’s Field diurnal variation) and feeds an error signal back to the current drivers which cancel the change. The loop response time is fast enough to cancel 50 or 60 Hz power line noise.

External input of 6 channels of analog data which are digitized to 24-bit (typically 6 picoTesla) resolution by the A/D convertor. This allows collection of data from the “instrument under test”. These measurements can be displayed on the controller front panel and/or transmitted to a remote computer.

                         

Front panel Vacuum Fluorescent Display indicating magnetic field values and resultant coil currents.

 

                        Front panel keyboard allows magnetic field settings and system calibration without a computer.

 

Single person system operation with a handheld RF remote control. This miniature (non-magnetic) control can be taken into the coil system with the operator, allowing tests /calibrations on the test item without the need for the operator to get in and out of the coil system. This is particularly useful when doing sensor axial alignments by “flashing” perpendicular fields on and off.

Labview control software that allows automatic control of magnetic field (rotating, static or stepped magnetic fields). The software can automatically collect linearity data and perform a “least squares fit” on the collected data set. Demonstration software available on request.

BILLINGSLEY AEROSPACE & DEFENSE 20936 Theseus Terrace, Germantown, Maryland 20876 301-540-8338 Phone 301-540-6231 FAX sales@billingsleyaerospace.com www.billingsleyaerospace.com

FEATURES:

Totally digital with no potentiometers to set

Active noise cancellation - system has two operating modes

- Closed loop operation with better than 90 dB rejection of changes in background magnetic field at DC and > 40 db at 60 Hz, allowing stable, noise free, operation of the system even with significant background noise.

- Open loop with the triaxial sense head monitoring the ambient field and transmitting the, 24-bit resolution field value over an RS232 link to a remote computer. This allows the operator to use software to subtract out the changes in ambient magnetic field without a Helmholtz coil system (i.e. to alternatively use the APEX-CS as a magnetic observatory). This mode is useful in situations where the size of the Helmholtz system, relative to the particular item under test, is too small to generate a uniform field value over the volume of the test item. The controller can be commanded in/out of the open loop mode under software or front panel control.

Stand alone or with a computer interface. The instrument front panel has a numeric keyboard which allows the user to control magnetic field values without a computer attached.

The front panel display indicates applied coil current for the X, Y and Z axes, magnetic field data from the triaxial sense head when in the observatory mode and field measurement data from the 4^th (single axis) calibration sensor. The 4^th sensor is connected by an 8 meter cable that allows the sensor to be placed in different orientations.

Automatic system calibration:

- The sequence is for the operator to place the single axis calibration sensor at the coil’s center along a given axis. The remote control is used to set the controller into a calibration mode and initiates a reading of the sensor’s output. The operator then “flips” (changes) the sensor orientation by 180 degrees along the axis being calibrated and depresses the “cal” button.

- The controller takes the average of the two readings and automatically corrects and stores the zero field offset error of the calibration sensor. Using this information it automatically adjusts the zero field setting for that coil axis. The cal sensor is then sequentially placed in each of the other two axes and the cal button depressed to adjust to zero field. The system now has it’s zero field settings accurately set. Similar cal sequences are used to set the calibration system field magnitude values and system orthogonality.

- A complete Helmholtz system calibration can be performed by a single person in < 5 minutes.

The entire system consumes < 180 Watts peak power (coil dependent) and is housed in a single instrument case of 37 W x 30 D x 13.5 H centimeters. It weighs < 7 kilograms.

* Available drive voltage/current from the APEX-CS controller is 48-24 volts @ 5 amps maximum. Existing coils must be capable of producing the (user) desired magnetic fields within this range to be compatible. Otherwise we recommend the use of the Billingsley 1 or 2.2 meter coils.

** Standby mode: power consumption can be reduced even further by turning power on to the coils only during the interval that the internal A/D Converter is acquiring data using the software interface provided. This reduces power consumption to near zero while still allowing the overall controller to remain powered up and ready for immediate use without warm up.

*** Calibration by comparison to a Proton Magnetometer standard recommended at 6 month intervals. This service is available from the factory if desired.

BILLINGSLEY AEROSPACE & DEFENSE 20936 Theseus Terrace, Germantown, Maryland 20876 301-540-8338 Phone 301-540-6231 FAX sales@billingsleyaerospace.com www.billingsleyaerospace.com

                        OPERATION:

                         

Totally digital

 

CMD-HHTX Remote Command Unit for the APEX-CS Helmholtz coil controller allows an operator to control magnetic fields from within the Helmholtz coil without need for another person.

- Standard operating frequency 418MHz (315 or 433.92 MHz options)

- Transmission range 100+ft.

- Choice of 256 selectable addresses

- Powered by a single 3 volt Lithium cell

- Compliant with limits for Class B digital devices pursuant to Part 15 of the FCC Rules.

- When any button is depressed the VFD display will indicate that the command is received

Remote Command Unit Button Assignments:

Button #	Function
1	X Axis Selection
2	Y Axis Selection
3	Z Axis Selection
4	Operation Mode - place the sensor in the X, Y or Z axis and depresses the axis button # 2, 3 or 4 as appropriate.
	First depression: a field is applied (i.e. 50,000 nT or whatever field value is pre-selected to be applied in this mode)
	Second depression: a field of the same value, but opposite in polarity is applied
	Third depression: zero field is applied
	This is a continuous toggle between the three states.
	Calibration Mode
	First depression: sets field to zero and records the reading of the single axis sensor (reverse or flip the sensor after this recording)
	Second depression: the controller stores the average of these two reading and uses that value as the zero "offset" zero of the sensor. This offset value is subtracted from all subsequent measurements and applies the same field value in the opposite polarity
	While still in this mode the user places the sensor in either the X, Y or Z axis and depresses the axis button # 2, 3 or 4 as appropriate. The controller then adjusts the Helmholtz field to true zero by setting an offset into the 20- bit D/A convertor for that axis. This offset is stored in non-volatile EEPROM.
5	First depression: sets the field to zero, pauses until stable then reads and stores values for the X, Y and Z axes of the instrument under test (IUT)
	Second depression: steps to 100,000 nT, pauses until stable then reads and stores as above
	Third depression: sets the field to +90,000 nT, measures values for the X, Y, and Z axes of the IUT until the setting decays to zero. The controller should flash the display or otherwise indicate when the field