ecmc Motion Control Module for EPICS

ecmc is a motion control and data acquisition module for EPICS-based systems, with support for motion axes, EtherCAT I/O, real-time control logic, and high-rate data acquisition.

Quick Start

1. Clone the repository.
2. Initialize submodules.
3. Use the ecmccfg repository to generate/configure a working IOC setup.

git submodule update --init --reference ./

Configuration scripts and examples are available in ecmccfg.

Features

Motion Control

• Motor record support

  • Absolute positioning
  • Relative positioning
  • Constant velocity
  • Evaluation of limit and reference switches
  • Homing (several sequences)
    • Low limit (refId = 1)
    • High limit (refId = 2)
    • Reference sensor via low limit (refId = 3)
    • Reference sensor via high limit (refId = 4)
    • Reference sensor center via low limit (refId = 5)
    • Reference sensor center via high limit (refId = 6)
    • Encoder index via low limit (refId = 11)
    • Encoder index via high limit (refId = 12)
    • Set position dedicated for auto restore (refId = 15)
    • Single-turn absolute encoder (resolver) reference via low limit (refId = 21)
    • Single-turn absolute encoder (resolver) reference via high limit (refId = 22)
    • Set position (refId = 25)

• Interlocks

  • Following error
  • Max speed
  • EtherCAT I/O
  • EtherCAT bus health

• Trajectories

  • Trapezoidal
  • Jerk-limited (Ruckig)
  • Custom
    • Calculated in ecmc PLC
    • Buffered positions from array (data storage)

• Advanced features

  • Virtual and normal axes
  • Modulo movements
  • Synchronization (to axis or any I/O) handled through expressions
    • Slaving: ax2.traj.setpos:=ax1.enc.actpos;
    • Sync: ax2.traj.setpos:=ax1.traj.setpos;
    • Phasing: ax2.traj.setpos:=ax1.traj.setpos+100;
    • Phasing with third axis: ax2.traj.setpos:=ax1.traj.setpos+ax3.traj.setpos;
    • Advanced: ax2.traj.setpos:=ax1.traj.setpos*sin(ax3.traj.setpos/100)+ec0.s2.VALUE;
    • Enable amplifiers: ax2.drv.enable:=ax1.drv.enable;
    • Interlock expression: ax2.mon.ilockfwd:=ec0.s1.INPUT_1 or ax1.enc.actpos < 100;

Data Acquisition

• Support for many different analog and digital slaves
• Up to 100 kHz analog and 1 MHz digital (oversampling slaves)

Control / PLC

• PLC objects can be created with custom sample rates where logic (including motion) can be handled in real-time
• Same expression syntax can be used for control and synchronization, for example:
  • ec0.s45.VALUE:=static.gain*77+ax2.traj.setpos/10;
• PLC variables can be accessed from EPICS
• More info: ecmc PLC configuration manual

Hardware Support

• Drives: stepper, servo, pulse-direction, and analog
• I/O: several analog and digital terminals
• Other: bus couplers, system terminals
• Current hardware list: https://github.com/paulscherrerinstitute/ecmccfg/tree/master/hardware

Setup and Configuration

The fastest way to get started is to use the configuration scripts in the ecmccfg repository.

ecmc is configured via EPICS IOC shell (iocsh).

Common iocsh Commands

• Create an ecmc application
  • ecmcAsynPortDriverConfigure <portName>,<paramTableSize>,<prio>,<disableAutoConnect>,<defaultSampleRateMS>
• Configure ecmc application and exit ecmc on error
  • ecmcConfigOrDie <ecmc ASCII command>
• Configure ecmc application (non-fatal on error)
  • ecmcConfig <ecmc ASCII command>
• Print available asyn parameters and other info
  • ecmcReport <detail>
  • asynReport <detail> (same as ecmcReport but also calls asynReport in other modules)

ecmc ASCII Command Examples

See the doxygen documentation for full details.

• Motion configuration
  • ecmcConfigOrDie "Cfg.CreateAxis(<axisid>,1,<type>)"
  • ecmcConfigOrDie "Cfg.SetAxisCntrlKp(<axisid>,<kp>)"
• EtherCAT bus configuration
  • ecmcConfigOrDie "Cfg.EcAddEntryComplete(<slaveid>,<vendorid>,<productid>,<dir>,<smid>,<pdoid>,<entryid>,<entrysubid>,<bits>,<name>)"
• EtherCAT slave configuration (SDO/SoE), example: set max motor current for EL7037 to 1500 mA
  • ecmcConfigOrDie "Cfg.EcAddSdo(<slaveid>,0x8010,0x1,1500,2)"
• PLC configuration
  • ecmcConfigOrDie "Cfg.CreatePLC(<plcid>,<sample rate ms>)"
  • ecmcConfigOrDie "Cfg.LoadPLCFile(<plcid>,<filename>)"
  • ecmcConfigOrDie "Cfg.AppendPLCExpr(<plcid>)=ax1.enc.homepos:=25#"

Documentation and Examples

• Manual
• Best-practice examples

Environment

ecmc runs best under these conditions:

• PSI environment (or ESS e3 environment)
• Real-time kernel patch (RT patch)
• Configuration via ecmccfg

Required EPICS Modules / Dependencies

• Open source EtherCAT master: https://etherlab.org/
• ExprTK: https://github.com/paulscherrerinstitute/exprtk-ecmc
• Motor: https://github.com/EuropeanSpallationSource/motor
• Asyn driver: https://github.com/epics-modules/asyn
• ecmccfg: https://github.com/paulscherrerinstitute/ecmccfg
• Ruckig: https://github.com/anderssandstrom/ruckig

Optional Modules

• ecmccomp: https://github.com/paulscherrerinstitute/ecmccomp

Plugins

Plugins with extra functionality that can be loaded during startup:

• CNC G-code support by grbl: https://github.com/anderssandstrom/ecmc_plugin_grbl
• SocketCAN support (including reduced CANopen support): https://github.com/anderssandstrom/e3-ecmc_plugin_socketcan
• FFT support via kissfft: https://github.com/paulscherrerinstitute/ecmc_plugin_fft
• Raspberry Pi wiringPi support: https://github.com/anderssandstrom/e3-ecmc_plugin_raspi
• PVA support from ecmc-plc: https://github.com/anderssandstrom/e3-ecmc_plugin_pva
• Simple scope for EtherCAT DC slaves: https://github.com/anderssandstrom/e3-ecmc_plugin_scope
• DAQ plugin: https://github.com/paulscherrerinstitute/ecmc_plugin_daq

Issues / Bug Reports

• https://github.com/epics-modules/ecmc/issues

Support

• ecmc: Anders Sandstrom (anders.sandstroem@psi.ch)
• Motor Record: Torsten Bogershausen (torsten.bogershausen@esss.se)
• ecmcMotorRecord model 3 driver (preferred): Anders Sandstrom (anders.sandstroem@psi.ch)