Marcel Grunder, EPICS Collaboration Meeting October 20081

Aerotech A3200 high precision rotation stage

Windows based Epics IOC driver implementation

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Aerotech components…

ABR1000 Air-Bearing Rot. StageATS125 Linear Stage

Ndrive + Npaq Amplifier

A3200 motion software

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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 Aerotech’s own AEROBasic or

RS274 G-code, C, C++, VisualBasic, Delphi and LabVIEW

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A3200 Software Architecture

Windows

RTX

Hardware Ndrive Npaq

motors

■ Layer 4: Windows Apps

■ Layer 3: Programming Interface

■ Layer 2: Nmotion SMC engine

■ Layer 1: Drive Firmware

IOC

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At a beamline

X-ray beam

exposure box

(filter)

cryojet

microscope

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Measurement mode timing diagram

Meas. time

osc. angle

time

angle

1. calc

Shutter Open

Open delay

PSO Open

Accl delay

Close delay

PSO-Close

M-Stop

PSO Open

Moving

2. move

3. Det. on4. move

M-Start

Start

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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. > 2.13 requires larger thread stack sizestatic const unsigned stackSizeTable[epicsThreadStackBig+1]

= {4000, 6000, 5000000};

■ A3200 without hardware behaves differently. Attention when testing limits, homing, errors…