5.2.1. DAQ Move

This module is to be used to control any actuator hardware. An actuator is, in a general sense, any parameter that one can control and may vary during an experiment. The default actuator is a Mock one (a kind of software based actuator displaying a position and accepting absolute or relative positioning). Introduction

This module has a generic interface in the form of a dockable panel containing the interface for initialization, the manual control of the actuator position and a side tree like interface displaying all the settings. Fig. 5.4 shows the minimal interface of the module (in order to take minimal place in the Dashboard)


Fig. 5.4 Minimal DAQ_Move user interface Hardware initialization

  • Stage: list of available hardware plugins of the DAQ_Move type.
  • Ini. Stage: Initialize the hardware with the given settings (see Plugins for details on how to set hardware settings.)
  • Quit: De-initialize the hardware and quit the module Positioning

Once the hardware is initialized, the actual position is displayed on the Current position display (bottom of Fig. 5.4) while the absolute position can be set using the top spinbox and apply it using the green_arrow button. Advanced positioning

More options can be displayed in order to precisely control the actuator by pressing the plus_button button. The user interface will then look like Fig. 5.5.


Fig. 5.5 DAQ_Move user interface with controls

The two new displayed spinbox relate to Absolute positioning (redundant with the one on the top) and Relative one.

  • home: the actuator will try to reach a home position (knwon position or physical switch limit)
  • abs: the actuator will try to reach the set Absolute position
  • move_rel: the actuator will try to reach a relative position (+increment)
  • move_rel_m: the actuator will try to reach a relative position (-increment)
  • where: will update the current position display
  • stop: stop the current motion (if possible) Settings

The hardware and module settings can be displayed in order to initialize correctly the actuator and add other options by pressing the settings button. The user interface will then look like Fig. 5.6.


Fig. 5.6 Full DAQ_Move user interface with controls and settings

In the settings tree, there is two sections. The first relates to Main settings (not much there for the moment apart for the selected stage type and Controller ID that is related to multiaxes controller. The second relates to the hardware settings (the ones the hardware will need in order to initialize…). There is also specific settings explained below. Multiaxes controller

Sometimes one hardware controller can drive multiple actuators (for instance a XY translation stage). For this particular case the controller should not be initialized multiple times. One should identify one actuator refered to as Master and the other ones will be referred to as Slave. They will share the same controller address represented in the settings tree by the Controller ID entry. These settings will be activated within the plugin script where one can define a unique identifier for each actuator (U or V for the conex in Fig. 5.6).

  • Controller ID: unique identifier of the controller driving the stage
  • is Multiaxes: boolean
  • Status: Master or Slave
  • Axis: identifier defined in the plugin script

See daq_move_Template.py for a detailed example. These settings are really valid only when the module is used within the Dashboard framework that deals with multiple modules at the same time as configured in the Preset manager interface. Bounds

if this section is activated (by clicking the Set Bounds entry) then the actuator positions will be software limited between min and max. This can be used to prevent the actuator to reach dangerous values for the experiment or anything else. Scaling

If this section is activated (by clicking the Use scaling entry) then the set and displayed positions will be scaled as:


This can be useful for instance when one deals with translation stage used to delay a laser pulse with respect to another. In that case it is easier to work with temporal units such as femtoseconds compared to mm or other native controller unit. Other settings

  • epsilon: -very important feature- the actuator will try to reach the target position with a precision epsilon. So one could use it if one want to be sure the actuator really reached a given position before moving on. However if the set precision is too small, the actuator may never reached it and will issue a timeout
  • Timeout: maximum amout of time the module will wait for the actuator to reach the desired position.