====== PLC variables ======
There is a settings file which specifies in which mode we are communicating: mpi or spi along with mode settings.

Then on program screen we have a checkmark "Use External", which enables communication.

Then on customer side there is some kind of variables which we are working with. Including variables which we are using to write results.

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**cam_mode** - read only. Double variable. Though variable is double, the value should be an integer number.

Gets mask number which should be used by the program for analysis. In program we have several masks:
  * 0-Matches
  * 1-Box
  * 2-Broken box
  * 3-Squares
  * 4-Focus
"Squares" was giving the best results, so it is always used.
Focus is just there to get focus value.

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**cam_picture** - read only. Double variable. Though variable is double, the value should be an integer number.

Enables saving of image each interval specified on program screen(can be 0 to save every image).
Images are saved into "stored pictures" folder.

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**cam_process** -  read only. Double variable. Though variable is double, the value should be an integer number.

Enables buffer processing. 
Program saves received images into memory queue without processing. If enabled - program gets images from queue and analyzes them in separate thread.

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**cam_counter** - Write only.

Number of image after processing.

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**cam_X** - Write only.

Position X of found marker.

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**cam_Y** - Write only.

Position Y of found marker.

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**cam_focus** - Write only.

Focus value.

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**cam_filename** - Write only. Byte array.

stored filename(if storage enabled)

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**cam_flag** - Write only.

Signals with 1 that program is done analyzing image and ready for the next one.
This variable should be automatically reset to 0 after set.