Main Index

• Introdution
  
  • Installation
    
    • Library Files
      
  • Library Activity
    
  • Camera layout
    
• DCL Functions
• Camera Trigger

Introdution

This series of libraries allows for the complete management of CCD DTA cameras.
They have been made using the classic DLL technique, or the library for UNIX;
With this modality all you need to do is declare the include dcl.h file within your own C programme to obtain complete access to the library.
To become familiar with the procedures available you should first of all examine the test.dsw
example project, which can be opened with the Visual C++ 6.0.
This library runs on Windows 32-bit platforms such as Win95/98, NT, Windows 2000, XP or LINUX.

Installation

The installation of the library is of course always linked to the installation of the camera :

1. If requested by your camera model you must install the interface card , and the low level driver. For more informations always refer to the camera manual.
   
2. Copy the Library Files into your working directory.
   

Library Files

When you copy the files of the library into the work directory you have to be well aware of the necessary ones:

1. dcl directory : there are two files for the library configuration: camera.cfg to list the settings of the currently selected camera, dcl.cfg to list the CCD and platform parameters, also (not necessary) can be present an image raw files (eia1956.raw as default) for the demo camera mode.
   
2. dcl.dll and dcl.lib for Windows or dcl.a for Linux : this is the library !
   
3. dcl.h and dcldef.h are definition files for C/C++ language; they are necessary to compile and link the library to its own C/C++ code.
   
4. ftd2xx.dll this library file must always present, the library use it to access at USB 1.1 port.
   
5. dcs.exe or simply dcs under linux, this is the camera configurator. With this utility you can change the selected camera and modify every present parameters.
   
6. io.dll library used by all cameras with the parallel port (EPP) as main interface under XP/2000 operating system.
   
7. pydcl.dll and pydcllib.py if you want control the camera via the python interpreter.

Library Activity

The DCL library allows one to use DTA CCD cameras very easily and, at the same time, achieve complex working modes, if required. Of course, any time you call the library [DC_Open()] it performs some basic operations :

1. Search of the selected interface;
   
2. Search of the presence of the camera;
   
3. Initialization of the camera;
   
4. Storage allocation for transfers in DMA;
   
5. Background task activation.
   

On the other hand, as we close the library connection [DC_Close()], it carries out the following operations :

1. Memory deallocation transfers in DMA.
   
2. Deactivation task in background.
   
3. Interface deactivation resources.
   

Point 5 carried out by the DC_Open() is an essential one as it performs two basic activities twice per second :

1. Clear CCD
   
2. Temperature Control.
   

The CCD cleaning is very important as it naturally tends to store charge. Because of this, it needs to be read fictitiously to keep it perfectly clean.

The temperature control is an operation typically required by cooled cameras, as it is necessary to select and keep the CCD sensor operative temperature stabilized.

In pratice every 500 ms the background task carries out the CCD cleaning, the reading of its temperature and, if necessary, the writing on D/A running the cooler power. It goes without saying that such operations have to be synchronized with the reading operations of the camera, or even disabled if necessary.[DC_StartNow() or DC_StopNow()].

Camera layout

Connecting the camera to its personal computer using various types of interface, from the simple parallel port, used for the printer, to the link on USB or the proprietary interface DTA FDL-PCI with possibility of parallel link or up optic fibre is possible.
When instead it is necessary to realize an array of cameras the obligation interface to be used is the FDL-PCI.
Choosing between two different typologies is possible to use this mode:

1. He it can choose to use a suitable multiplexer, this allows to connect as far as four cameras to a FDL-PCI single card.
   The advantage is that with an individual slot PCI it is possible to check four cameras, the disadvantage is that the download of the cameras is sequential. Also it is not possible to control the instrument via fiber-optic link. Simultaneus shot of the four cameras is guaranteed.
2. Another possibility is to use more FDL-PCI cards, up to a maximum than eight, than they allow the click and the simultaneous download than the eight cameras. It is possible to control the instrument via fiber-optic link.