EPICS Developments at the Australian Synchrotron - PowerPoint PPT Presentation

About This Presentation
Title:

EPICS Developments at the Australian Synchrotron

Description:

Ability to read two encoders at all times per motor. The encoder used in the motor record can be swapped at run time while the motor is stopped ... – PowerPoint PPT presentation

Number of Views:73
Avg rating:3.0/5.0
Slides: 16
Provided by: tay71
Category:

less

Transcript and Presenter's Notes

Title: EPICS Developments at the Australian Synchrotron


1
EPICS Developments at the Australian Synchrotron
DSP EPICS driver for the General Standards 16AIO
analog card EPICS driver for the Galil range of
motor controllers Author Mark Clift Presented
by Nicholas Hobbs
2
1. Analog Acquisition
  • Many Analog acquisition cards are used, the 16AIO
    from General Standards is the most commonly used
    on site
  • 16AIO card linearity and noise characteristics
    are average for a 16 bit card
  • 16AIO is faster than average (300K samples
    cumulative), allowing DSP methods to be applied
    within the EPICS driver
  • The 16AIO is a mezzanine board and is available
    in many form factors, we use PCI at the
    Australian Synchrotron

3
16AIO EPICS Driver
  • The 16AIO EPICS Driver was created using the
    IP330 driver as initial basis
  • It has an Asyn based structure and is compatible
    with the fast PID feedback software written by
    Mark Rivers
  • 16AIO hardware includes a 32Kb sample buffer
    which allows rapid data acquisition
  • At the driver layer, sample rates up to 30 KHz
    are used
  • The maximum EPICS update rate is 1.5 KHz
  • Achievable speed depends on computing hardware,
    operating system, and machine load.

4
16AIO Updates to registered clients (eg. EPICS)
  • The 16AIO driver functionality is based on
    regular updates to registered clients (eg. EPICS
    layer) via Interrupt I/O
  • Fundamental frequency of updates to clients is
    specified by the LcaioSetup comand
  • Update frequency of individual signals is
    specified by a combination of the fundamental
    update frequency and the LcaioAiSignalSetup
    command. The LcaioAiSignalSetup command simply
    divides the fundamental update frequency by an
    integer

5
16AIO DSP methods
  • Two very basic DSP methods are employed by the
    16AIO driver, they are
  • Sample Averaging
  • Effective number of bits (ENOB)
  • The ENOB and averaging algorithms do not operate
    when only one sample is available per client
    update period, multiple samples are required
  • The effective bit (ENOB) resolution of the
    resultant data is calculated from the following
  • Fos 4w x fs
  • Fos Sampling frequency used
  • fs Original sampling frequency requirement
  • W Extra bit(s) of resolution

6
Uses of 16AIO at the Australian Synchrotron
  • Fast feedback system on the Microspectroscopy
    beamline
  • General analog inputs at the Imaging beamline
  • Booster and Storage ring current measurement (see
    below, red line)

7
2. Galil EPICS driver for motor control
  • The Galil driver has a native EPICS driver/device
    layer, and does not use Asyn
  • Galil driver interfaces with the motor record and
    a collection of standard EPICS records
  • The standard records are used to provide
    control/monitor interfaces for features that the
    motor record does not support (e.g. gear ratio)
  • The Galil driver is compatible with all motor
    controllers in the Galil range
  • The Galil driver has an extensive list of
    parameters which can be difficult for first time
    users to comprehend

8
Galil EPICS driver
  • The Galil driver has many unique features
    including
  • Ability to accept and work with user-written
    Galil code
  • Ability to read two encoders at all times per
    motor. The encoder used in the motor record can
    be swapped at run time while the motor is stopped
  • A generic interface is provided so new
    functionality can be added to the driver, whilst
    providing a full EPICS interface
  • Allows master/slave relationships amongst motors
  • Has closed loop stepper control that is
    compatible with master/slave relationships

9
Galil EPICS driver
  • Further features
  • Stall detection of any active encoder that is
    related to a motor
  • EGU travelled after limit activation can be
    specified, useful for tricky switches, or fast
    moving heavy loads

10
Galil controllers in use at Australian Synchrotron
Location Motor count
Powder diffraction - End station 24
Powder diffraction - Diffractometer 4
X-ray Absorption - End station 24
SAXS/WAXS - End station 28
SAXS/WAXS - IVU 2
Infrared - End stations 17
Protein Crystallography - IVU 2
Microspectroscopy - End station 16
Microspectroscopy - IVU 2
Imaging beamline - Wiggler 2
Imaging beamline - End stations 36

Total 157














11
Galil controller models that we use
  • MC 8000
  • Based on the 2183 Galil motor controller
  • Eight axis, integrated parker drive system
  • Beamline and End station motors
  • Front Internal Rear

12
Galil controller models that we use
  • MC 4000/2000
  • Based on the 2143/2123 Galil motor controller
  • Four/two axis, external drive system
  • Insertion devices, and heavy equipment (e.g.
    SAXS/WAXS table)
  • IVU Control rack IVU

13
Galil motor controllers, our impression
  • Reliable, had no hardware failures
  • Easy to use and quick to get going
  • In comparison we have had many hardware failures
    in PC-104 Delta Tau controllers, particularly the
    communications board
  • AS very satisfied with Galil support (e.g. They
    provided generic SSI encoder interface firmware)

14
Thank you for your attention
Australian Synchrotronwww.synchrotron.vic.gov.au
www.synchrotron.org.au
15
For more information and software
  • DSP EPICS drivers for 16AIO analog card
  • EPICS drivers for Galil motor controllers
  • Mark Clift
  • mark.clift_at_synchrotron.org.au
  • ftp.synchrotron.org.au/pub/EPICS09
Write a Comment
User Comments (0)
About PowerShow.com