pvaDriver
=========

An areaDetector pvAccess driver

:author: Bruno Martins, Brookhaven National Laboratory

.. contents:: Contents

Introduction
------------

This is an :doc:`../index` driver for importing an EPICSv4 NTNDArray via 
pvAccess into areaDetector. It does so by creating a monitor on the specified 
PV.

This driver inherits from :doc:`../ADCore/ADDriver`. It implements some of the
parameters in `asynNDArrayDriver.h`_ and in `ADArrayDriver.h`_, namely:

+ ADManufacturer
+ ADModel
+ ADAcquire
+ ADImageMode
+ ADNumImages
+ ADMaxSizeX and ADMaxSizeY
+ ADMinX and ADMinY
+ ADBinX and ADBinY
+ ADReverseX and ADReverseY
+ ADSizeX and ADSizeY
+ ADNumImagesCounter
+ NDArraySize, NDArraySizeX and NDArraySizeY
+ NDDataType and NDColorMode
+ NDArrayCounter

It also implements a few parameters that are specific to the pvAccess driver.


pvAccess driver specific parameters
-----------------------------------

The pvAccess driver-specific parameters are the following:

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  * - Parameter Definitions in pvaDriver.cpp and EPICS Record Definitions in pvaDriver.template
  * - Description
    - EPICS record name
    - EPICS record type
  * - Number of overruns occurred
    - $(P)$(R)OverrunCounter, $(P)$(R)OverrunCounter_RBV
    - longout, longin
  * - Name of the PV to monitor. This can be changed a run-time.
    - $(P)$(R)PvName, $(P)$(R)PvName_RBV
    - waveform, waveform
  * - Status of the connection to the server
    - $(P)$(R)PvConnection_RBV
    - bi


Configuration
-------------

The pvaDriver driver is created with the pvaDriverConfig command, either from
C/C++ or from the EPICS IOC shell. ::

    int pvaDriverConfig(const char *portName, const char *pvName,
                          int maxSizeX, int maxSizeY, int dataType,
                          int maxBuffers, size_t maxMemory,
                          int priority, int stackSize)

The pvaDriver-specific fields in this command are:

+ ``pvName`` Name of the PV to be monitored.

For details on the meaning of the other parameters to this function refer to
the detailed documentation on the pvaDriverConfig function in the
`pvaDriver.cpp documentation`_ and in the documentation for the constructor
for the `pvaDriver class`_.

Example st.cmd startup file
---------------------------

.. toctree::
   :hidden:
   
   st_cmd.rst

There is an example IOC boot directory and startup script provided with pvaDriver: :doc:`st_cmd`.

MEDM screens
------------

The MEDM screen for the pvaDriver is shown below.

.. image:: ADPvaDriver.png


.. _pvaDriver.cpp documentation: ../areaDetectorDoxygenHTML/pva_driver_8cpp.html
.. _asynNDArrayDriver.h: ../areaDetectorDoxygenHTML/asyn_n_d_array_driver_8h.html
.. _ADArrayDriver.h: ../areaDetectorDoxygenHTML/_a_d_driver_8h.html
.. _pvaDriver class: ../areaDetectorDoxygenHTML/classpva_driver.html