Aerotech A3200 high precision rotation stage

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Aerotech A3200 high precision rotation stage

• Windows based Epics IOC driver implementation

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Aerotech components
ABR1000 Air-Bearing Rot. Stage ATS125 Linear Stage
A3200 motion software
Ndrive Npaq Amplifier
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Aerotech SMC controller

• Motion control system and programming environment
  
• Runs on a standard Windows PC
• Maximum of 32 intelligent drives connected via
  IEEE 1394
• 20 kHz servo update rate for all axes
• Integrated high-speed Position Synchronized
  Output (PSO) for position latching.
• Utility Programs to configure, troubleshoot, and
  operate the controller
• Programming interfaces include Aerotechs own
  AEROBasic or RS274 G-code, C, C, VisualBasic,
  Delphi and LabVIEW

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A3200 Software Architecture
IOC

• Layer 4 Windows Apps
• Layer 3 Programming Interface
• Layer 2 Nmotion SMC engine
• Layer 1 Drive Firmware

Windows
RTX
Hardware Ndrive Npaq motors
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At a beamline
cryojet
exposure box (filter)
X-ray beam
microscope
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Measurement mode timing diagram
Close delay
Open delay
PSO Open
M-Stop
angle
Shutter Open
PSO-Close
PSO Open
Accl delay
1. calc
osc. angle
M-Start
2. move
Start
3. Det. on 4. move
Meas. time
time
Moving
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Epics driver requirements

• Fast signal indicating "movement done"
• A3200 PSO feature used to open/close fast beam
  shutter
• Safe homing sequence for multiple axes stages
• Measurement mode
• Define start oscillation angle and oscillation
  time
• Use calc records to generate movement start
  stop pos, shutter open close pos and velocity.
• Direct mode
• Absolute or incremental move of axis (axes) at
  defined speed

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Software environment

• Runs on Windows XP
• EPICS base 3.14.8
• autosave and restore 4-2-1
• store offset and velocities
• state notation language (SNL) 2.0.1
• homing sequence
• A3200 v.2.19

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A3200 programming models

• Library Programming Model
• Simplest programming model used to initialize
  controller, to get controller and motor status
  info
• CNC Programming Model (G code)
• compiled and loaded as binary code, directly into
  the Nmotion SMC controller.
• Runs in RTX real time environment

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A3200 programming models (cont.)

• Mixed Programming Models
• There is no explicit synchronization between the
  CNC tasks and Windows threads.
• To synchronize use G-code global variables and
  CALLBACK statement.
• In C userCallback()
• Get the G-code Task number
• Set the correct moving flag
• scanIoRequest()
• epicsEventWaitWithTimeout()

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Difficulties

• Long time performance was limited by automatic
  updates.
• Updates done manually while no user operation.
• McAfee Antivirus could disturb long time
  measurements when McShield service started.
• McShield will be restarted before user operation
  starts.
• A3200 v. gt 2.13 requires larger thread stack size
• static const unsigned stackSizeTableepicsThreadSt
  ackBig1 4000, 6000, 5000000
• A3200 without hardware behaves differently.
• Attention when testing limits, homing, errors