= Consideration to use Basler a2A series =
  KAGRA uses {{{acA640-120gm}}} cameras as the GigE system. Cameras are controlled by {{{pylon-camera-server}}} developed in LIGO. When considering the use of a Basler cameras with {{{pylon-camera-server}}} also for TCam, {{{a2A5328-4gmPRO}}} was listed up as a candidate that satisfies the specification requirements. We then verified the compatibility between {{{a2A5328-4gmPRO}}} and {{{pylon-camera-server}}}.

== Conclusion ==
  * There was no compatibility between {{{a2A5328-4gmPRO}}} as SDK/GenlCam 2.x and {{{pylon-camera-server}}} as SDK/GenlCam 1.x.
  * The best solution from the view point of human resources is to find another camera as SDK/GenlCam 1.x which satisfies the specification requirements.
  * It's possible to modify {{{pylon-camera-server}}}, but many changes and great efforts are required.
    * Modifying {{{pylon-camera-server}}} to make compatibility with both 1.x and 2.x is not so fruitful because 3.x and 4.x already exist.
    * So, the 2nd best solution may be to fork {{{pylon-camera-server}}} as {{{pylon-camera-server2}}} which is compatible only with 2.x if {{{a2A5328-4gmPRO}}} is really used at the very limited places.

== First trial ==
  * Config file was prepared as {{{/kagra/camera/pylon-camera-config/K1-CAM-TEST0.ini}}}. Different settings are only resolution (5328x4608 instead of 640x480) and frame rate (4fps instead of 25fps) as follows.
  {{{
width=5328
height=4608
framerate_numerator=4
  }}}
  * Camera server can be launched by following command.
  {{{
> /kagra/camera/pylon-camera-service start TEST0
  }}}

  * EPICS IOC was running but camera images cannot be received by camera_client because pylon-camera-server showed a following error.
  {{{
Feb 18 15:42:55 k1cam2 systemd[750]: Started pylon-camera-server@K1-CAM-TEST0.service - Basler 2D GigE camera RTP H264 UDP server.
Feb 18 15:42:55 k1cam2 pylon-camera-server[2132807]: Obtained request pad src_0 for appsink branch.
Feb 18 15:42:55 k1cam2 pylon-camera-server[2132807]: Obtained request pad src_1 for udpsink branch.
Feb 18 15:42:55 k1cam2 pylon-camera-server[2132807]: Starting main loop.
Feb 18 15:42:55 k1cam2 pylon-camera-server[2132807]: cas warning: Configured TCP port was unavailable.
Feb 18 15:42:55 k1cam2 pylon-camera-server[2132807]: cas warning: Using dynamically assigned TCP port 38533,
Feb 18 15:42:55 k1cam2 pylon-camera-server[2132807]: cas warning: but now two or more servers share the same UDP port.
Feb 18 15:42:55 k1cam2 pylon-camera-server[2132807]: cas warning: Depending on your IP kernel this server may not be
Feb 18 15:42:55 k1cam2 pylon-camera-server[2132807]: cas warning: reachable with UDP unicast (a host's IP in EPICS_CA_ADDR_LIST)
Feb 18 15:42:55 k1cam2 pylon-camera-server[2132807]: The camera is connected.
Feb 18 15:42:55 k1cam2 pylon-camera-server[2132807]: Attaching camera.
Feb 18 15:42:56 k1cam2 pylon-camera-server[2132807]: Opening camera.
Feb 18 15:42:56 k1cam2 pylon-camera-server[2132807]: Device Model Name: a2A5328-4gmPRO
Feb 18 15:42:57 k1cam2 pylon-camera-server[2132807]: Parameter not found in CStringParameter::GetValue. (No node attached.)
  }}}

  * Accessing camera device was succeeded, but camera property cannot be obtained at the beginning of the server launching.


== Details ==
  * Differences that affect the use of {{{pylon-camera-server}}}
  ||<#CCCCFF>            ||<#CCCCFF>'''acA640-120gm'''           ||<#CCCCFF>'''a2A5328-4gmPRO'''      ||
  || Maximum resolution  || {{{659×494}}}                        || {{{5328×4608}}}                   ||
  || Maximum frame rate  || {{{120}}}                            || {{{~4.8}}}                        ||
  || SDK/GenlCam version || {{{1.x}}}                            || {{{2.x}}}                         ||
  ||<|6> Class members   || {{{camera.GevCurrentIPAddress}}}     || {{{device (*1)}}}                 ||
  ||                        {{{camera.DeviceID}}}                || {{{camera.DeviceSerialNumber}}}   ||
  ||                        {{{camera.AcquisitionFrameRateAbs}}} || {{{camera.AcquisitionFrameRate}}} ||
  ||                        {{{camera.ResultingFrameRateAbs}}}   || {{{camera.ResultingFrameRate}}}   ||
  ||                        {{{camera.ExposureTimeRaw}}}         || {{{camera.ExposureTime}}}         ||
  ||                        {{{camera.GainRaw}}}                 || {{{camera.Gain}}}                 ||


  * Some of different class members are used in the main infinite-loop as follows, so it's difficult to insert version check for each call of member class.
  {{{
while (1) {
    ~
    ~
    if (epics_exposure_time_raw_set > 0) {
        g_print("Setting exposure time: %i\n", epics_exposure_time_raw_req);
        camera.ExposureTimeRaw.TrySetValue((int64_t) epics_exposure_time_raw_req, Pylon::IntegerValueCorrection_Nearest);
        exposure_time_raw_set = 0;
    }
    exposure_time_raw = camera.ExposureTimeRaw.GetValue();
    ~
    ~
}
  }}}


  * A wrapper class defined at the out of main loop as follows is required for '''all methods in all different classes''' because the class type is also different.
  {{{
std::function<void(double)> setExposure;
std::function<double(void)> getExposure;

GenApi::INodeMap& nodemap = camera.GetNodeMap();
if (GenApi::CIntegerPtr(nodemap.GetNode("ExposureTimeRaw")).IsValid()) {
    GenApi::CIntegerPtr node = nodemap.GetNode("ExposureTimeRaw");
    setExposure = [node](double v) {
        node->SetValue((int64_t)v);
    };
    getExposure = [node]() -> double {
        return (double)node->GetValue();
    };
}
else if (GenApi::CFloatPtr(nodemap.GetNode("ExposureTime")).IsValid()) {
    GenApi::CFloatPtr node = nodemap.GetNode("ExposureTime");
    setExposure = [node](double v) {
        node->SetValue(v);
    };
    getExposure = [node]() -> double {
        return node->GetValue();
    };
}
  }}}

  * Then, we can keep a cycle speed of the main loop as follows.
  {{{
while (1) {
    ~
    ~
    if (epics_exposure_time_raw_set > 0) {
        g_print("Setting exposure time: %f\n", epics_exposure_time_raw_req);
        setExposure(epics_exposure_time_raw_req);
        exposure_time_raw_set = 0;
    }
    exposure_time_raw = getExposure();
    ~
    ~
}
   }}}

 * For {{{(*1)}}}, replacing method directly seems to work fine like as follows.
 {{{
   if (version=1) x = camera.GevCurrentIPAddress.GetValue());
   elif (version=2) x = device.GevIpAddress()
 }}}