spec - Local Sector 7 web page

AZIMUTH angle used in advanced modes (see the Four-Circle Reference) and the incidentX-ray wavelength, LAMBDA ,are also listed.The angular positions listed above are the user angles. You set user angles duringdiffractometer alignment to satisfy the premises of the geometry calculations, such asthe positions of the zeroes of the angles. Dial angles keep track of hardware limitsand prevent complete loss of angles from alignment errors or computer failure. Thedial angles are generally made to agree with a physical indicator on each motor, suchas a dial. User angles are related to the dial angles through the equation:user = sign × dial + offsetRedefining a user angle changes the internal value of offset. Dial angles are directlyproportional to the values contained in the hardware controller registers. The sign ofmotion is set in the configuration file by the spec administrator and normally isn’tchanged.The set_dial motor position macro is used to set the dial position of a motor. Theargument motor is the motor number or mnemonic. All motors have short mnemonics,such as tth , th , chi ,and phi .4.FOURC> set_dial tth 24.526Mon Feb 15 01:42:10 1994. Two Theta dial reset from 0 to 24.526.5.FOURC>The set motor position macro is used to set the user position of a motor (i.e., tochange offset). If you had a slit motor with mnemonic ts1 ,you might enter5.FOURC> set ts1 .5Mon Feb 15 01:43:31 1994. Top Slit1 reset from 0 to .5.6.FOURC>The wa (where all) macro lists both the user and dial positions of all configuredmotors.6.FOURC> waCurrent Positions (user, dial)Two Theta Theta Chi Phi Top Slit1 Bot Slit1tth th chi phi ts1 bs124.6310 12.3155 90.0000 0.0000 0.5000 -0.500024.5260 12.2155 89.7865 0.0950 0.5000 -0.50007.FOURC>8 USER MANUAL AND TUTORIALS INTERIM WORK-IN-PROGRESS (8/16/01) NOT FOR GENERAL DISTRIBUTION