Magnetic Lab Hall Probe Measurement System 8/26/2003 Key System Requirements Motion Control: SmartMotor via RS axis: x(0-400mm), y(0-400mm), z(0-6000mm), w(0-360) Motion Readout: Linear (x, y, and z) and Rotary (w) Encoders Linear encoder resolutions: 1 μm absolute position Rotary encoder resolutions: up to 0.1deg Linear stage speed: up to 150 mm/s (6m bench); 250mm (3m bench) Rotary stage speed: up to 1 Hz DAQ: Hall Voltage Measurement Resolution: 18 bit (5-1/2 digits), 0.1 Gauss out of 2 Tesla (1/200,000) Sampling rate: 1 kS/s (every 200 μm) Synchronization: Absolute Position vs. Voltage Measurement w/ at 1kS/s Triggering must be done using absolute position every step. Additional counter must be used to count the number of missing pulses from encoder (N=step/resolution) Digital I/O Noise Control: 10 -7

Magnetic Lab Hall Probe Measurement System 8/26/2003 Current System Architecture Quadrature PCI Card Counter PCI Card HP Multimeter (3458A) Triggering GPIB From x, y, z, and w encoders From the Hall Probe To the SmartMotors RS-485 Current Issues: 1.The resolution is limited by 5 micron due to overlapping of the signal from encoder, it mis-triggers the Multimeter. 2.Triggering signal is based upon A phase of the encoder signal, when the stage moves backward due to some jittering effect, it causes false triggering. 3.Effective resolution of the Hall voltage measurement is about 16bit due to the noise introduced from the lengthy cable. 4.Need remote control device to do fine alignment. 5.???

Magnetic Lab Hall Probe Measurement System 8/26/2003 Proposed System Architecture By Boris D. Key Features: 1.Integrate the Quadrature encoder readout card and the triggering counter card to produce “regulated” triggering signal. 2.The controller can be installed on the motion stage, shorten the digital I/O cabling to reduce the digital I/O noise. Drawbacks: 1.Lots in-house development to the Motion Controller. 2.Hall voltage measurement noise is still an issue. PC/104 Motion Controller HP Multimeter (3458A) Triggering GPIB From x, y, z, and w encoders From the Hall Probe To the SmartMotors RS-485 RS-232

Magnetic Lab Hall Probe Measurement System 8/26/2003 Alternative Approach Key Features: 1.Integrated real time encoder readout, triggering, and Hall voltage measurement. 2.TCP/IP Interface, securely access the system anywhere, anytime. 3.Commercial off-the-shelf product. 4.Same hardware can be used for the Integral “Stretch Coil” setup. Drawbacks: 1.Will not be able to fit on to the motion stage but sit right next to the bench. Internal Triggering From x, y, z, and w encoders From the Hall Probe To the SmartMotors RS-232 PXIFPGA I/O DMM TCP/I P