Using LudlStage (Last Updated 6/17/2020)

A Note on Hardware

The code for this project currently works on the Ludl MAC6000 microscope stage controller. It may be compatible with other Ludl stage controller models, but changes may need to be made to the source code as necessary.

The following functions were adapted from https://github.com/DIDSR/eeDAP/tree/master/src/stages/Ludl:

• stage_check_busy_Ludl
• stage_get_joy_speed_Ludl
• stage_get_pos_Ludl
• stage_move_Ludl
• stage_open_Ludl
• stage_send_com_Ludl
• stage_set_joy_speed_Ludl
• stage_set_origin_Ludl

Connecting to the Stage with stage_open_Ludl

To open connection to the stage, run the command

ludl = stage_open_Ludl

If you have not connected to the stage before, you will prompted to enter which COM port the stage is connected to, which is something you will have to figure out manually. Once you have made your selection, your choice will be stored in a file named PortNames.mat inside the LudlStagedirectory, so you won't be queried in the future. If you change which COM port the stage is connected to, you will have to delete PortNames.mat and rerun stage_open_Ludl.

As a note, SerialPortSetup is the specific function called within stage_open_Ludl that creates Portnames.mat. There is no need to call it manually unless you do not want to go through stage_open_Ludl to do so.

Checking the Stage for Activity

The stage can be checked to see if it is currently performing any commands using

busy = stage_check_busy_Ludl(ludl)

where busy is a boolean indicating whether the stage is busy or not. This function is called within several of the functions.

Querying and Changing Position in Ludl Coordinates with stage_get_pos_Ludl and stage_move_Ludl

Commands involving the stage's location coordinates are written in units of Ludl tick marks. Each Ludl tick mark is 50 nm.

To get the stage's position in Ludl coordinates, use the command

[x_cor,y_cor] = stage_get_pos_Ludl(ludl).Pos

[x_cor,y_cor] gives the values of the x and y coordinates respectively of the stage in units of Ludl tick marks.

It should be noted that stage_get_pos_Ludl returns more properties of the Ludl stage object than you will probably need, so it is helpful to only extract a single property, such as Pos.

To move to a specific Ludl coordinate, use the command

stage_move_Ludl(ludl, [target_x_pos target_y_pos])

target_x_pos and target_y_pos are both in units of Ludl tickmarks. It should be noted that stage_move_Ludl moves to an absolute position as opposed to a position relative to where the stage last was.

Unit Conversion Between mm and ticks

mm2tick and tick2mm are unit conversion functions that convert from milimeters to ticks and vice versa respectively. They can be implemented as shown:

dist_tick = mm2tick(ludl, dist_mm) dist_mm = tick2mm(ludl, dist_tick)

Controlling the Stage with a Joystick

stage_get_joy_speed and stage_set_joy_speed can be used to get and set the joystick speed of the hub controller. We have not tested these functions and they seem to still be in development. It is not recommended to use them.

Setting the Stage Origin with stage_set_origin_Ludl

The purpose of stage_set_origin_Ludl is to set the origin of the Ludl coordinate system to the top left corner of the stage. It should be noted that the range and size of the tickmarks remain the same. The process can be implimented with the following command:

ludl = stage_set_origin_Ludl(ludl)

Checking for Errors using error_show

This function can be used to identify errors as shown:

error_show(ME)

where ME is a Matlab Exception structure with the following fields:

• identifier
• message
• cause
• stack (array of structures)
  • file (file name where error occured)
  • name (function name where error occured)
  • line (where error occured)

This function is called within most of the other functions to catch errors, so they serve as good examples of how this function can be implemented.

Closing Connection to the Stage with stage_close

Connection to the stage can be closed using stage_close(ludl)