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Motion Control
Much of the information below is originally derived from LARMOR, in most cases it would apply to any instrument.
Fixed setpoints for various devices are defined in appropriately named text files held in the C:\Instrument\Settings\config\NDXLARMOR\motionSetPoints\ directory.
An example file for the PGC (Polariser, Guide, Collimator) device is given here:
File path: C:\Instrument\Settings\config\NDW1298\configurations\motionSetPoints\pgc.txt
Polariser -2
Guide 0
Collimator 2
If you have multiple devices, for example you needed to setup setpoints for monitors 3 & 4, you would create similar text files in the following locations:
c:\Instrument\Settings\config\NDXLARMOR\motionSetPoints\monitor3.txt
c:\Instrument\Settings\config\NDXLARMOR\motionSetPoints\monitor4.txt
From the motion control point of view the two devices are identical. Each has a motor with an IN and an OUT position, like monitors 3 and 4. Each also has a motor to control the angle. The motor moves in a straight line tangential to the axis, so the transformation is angle = tan (motor position / separation).
The conversion is performed using a soft motor, as documented in the motor record. Note that soft motors require devSoftMotor.dbd and softMotor.dll to be included.
The setpoint lookup files for these devices define positions for both motors.
The two-tier sample changer contains four slots, each of which holds a rack. Several different types of rack are available. The positions of the slots and the layouts of the different types of rack are defined in rack_definitions.xml. It is unlikely these will need to change often.
The current state of the sample changer, i.e. which rack type is loaded into each slot and the offsets of the racks compared to their nominal positions, is stored in samplechanger.xml.
Putting to the PV SAMPCHNG:RECALC will cause these files to be read and a new sample position lookup file to be generated and loaded. This can be done by pressing recalculate in the Sample Changer OPI.
Please see the following page for guidance: Limits
Please see the following page for guidance: Home