Model 2G800

Sample Handler selection is determined by the degaussing system in use:

• Model 2G801 is for systems without an in-line degaussing system. Continuous rotation speeds of up to 5 Hz are possible to facilitate synchronous design schemes for the measurement of extremely weak rock magnetism (total moments less than 10·8 emu).
• Model 2G802 is for systems with an in-line 2-axis degaussing system. Three-axis degaussing is done by degaussing with the axial coil, translating to and degaussing with the transverse coil, rotating 90°, and degaussing again with the transverse coil.
• Model 2G803 is for single in-line transverse degaussing coil systems. Three-axis degaussing is possible with an optional flip mechanism.

The movements of the Sample Handler are controlled by the 2G810 Sample Handler Controller. This unit has an RS232 serial data link that communicates with an external computer. Sample translation and rotation are started by issuing high-level commands over the serial data link. Sample movement parameters such as acceleration, velocity, and linear or rotational movement intervals are all user-programmable. The Sample Handler Controller also has two limit switches for translation (left and right) that stop the translation motor when activated, and a home sensor for both translation and rotation.

The output stepper motor signals from the Sample Handler Controller are fed to the 2G820 Sample Handler Drive. This unit contains two power drivers that send pulses to the stepper motors. The power supplies contain constant current drivers with a compliance of approximately 30 volts, which provides rapid and smooth acceleration of the Sample Handler. The stepper motors require 200 pulses per revolution. For translation, this produces a movement of 0.65 mm per pulse. For rotation, the angular displacement for one pulse is 3.6°.