A PC-based real-time Hall probe automatic measurement system for magnetic fields

A real-time, Hall-probe automatic measurement system was developed at the S ynchrotron Radiation Research Center (SRRC) for the magnetic field measurem ent of the "C"-type rectangular combined function bending magnet, multipole magnets, and the insertion device magnets. The sampling rate on the x-y-z table with dynamic moving speed of 15 cm/s can be up to 200 samples/s, and the precision is within +/-0.01%. A PC is used as a system controller which connects instrument function cards with instruments via the PC bus and an IEEE-488 interface card. An inexpensive, stable within +/-15 ppm current so urce is produced to supply a high-stability constant current for the Hall p robe; a temperature controller maintains the Hall probe temperature within +/-0.2 degrees C. The system's software has been divided into different mod ules that can be connected into a network global data base. System testing has shown that the magnetic held measurement accuracy of this system is bet ter than +/-25 ppm in the static measurement.