a4c75d60bc
git-svn-id: https://subversion.xor.aps.anl.gov/synApps/areaDetector/trunk@7583 dc6c5ff5-0b8b-c028-a01f-ffb33f00fc8b
142 lines
5.7 KiB
HTML
Executable File
142 lines
5.7 KiB
HTML
Executable File
<HTML>
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<HEAD>
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<TITLE>areaDetector Simulation driver</TITLE>
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</HEAD>
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<BODY>
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<CENTER>
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<H1>areaDetector Simulation driver</H1>
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<H2> September 5, 2008</H2>
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<H2> Mark Rivers</H2>
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<H2> University of Chicago</H2>
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</CENTER>
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<P> </P>
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<CENTER><H2>Contents</H2></CENTER>
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<UL>
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<LI><A href="#Overview">
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Overview</A>
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<LI><A href="#Performance measurements">
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Performance measurements</A>
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<LI><A href="#Hardware notes">
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Hardware notes</A>
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<LI><A href="#Restrictions">
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Restrictions</A>
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</UL>
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<CENTER><H2><A name=Simulation_detector_driver>
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Simulation detector driver</A></H2></CENTER>
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simDetector is a driver for a simulated area detector. It inherits from ADDriver. The simulation detector implements
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nearly all of the parameters defined in ADStdDriverParams.h, with the exception of the file saving parameters, which is does not
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implement. It also implements a few parameters that are specific
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to the simulation detector. The simulation detector is useful as a model for writing real detector drivers. It is
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also very useful for testing plugins and channel access clients.
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This is part of the definition of the simDetector class:
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<PRE>
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class simDetector : public ADDriver {
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public:
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simDetector(const char *portName, int maxSizeX, int maxSizeY, NDDataType_t dataType,
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int maxBuffers, size_t maxMemory);
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/* These are the methods that we override from ADDriver */
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virtual asynStatus writeInt32(asynUser *pasynUser, epicsInt32 value);
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virtual asynStatus writeFloat64(asynUser *pasynUser, epicsFloat64 value);
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virtual asynStatus drvUserCreate(asynUser *pasynUser, const char *drvInfo,
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const char **pptypeName, size_t *psize);
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void report(FILE *fp, int details);
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</PRE>
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The portName, maxBuffers, and maxMemory arguments are passed to the ADDriver base class constructor. The maxSizeX, maxSizeY, and
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dataType arguments are specific to the simulation driver, controlling the maximum image size and initial data type of the
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computed images. The writeInt32 and writeFloat64 methods override those in the base class. The driver takes action
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when new parameters are passed via those interfaces. For example, the ADAcquire parameter (on the asynInt32 interface) is
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used to turn acquisition (i.e. computing new images) on and off.
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<P>
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The simulation driver initially sets the image[i, j] = i*gainX + j*gainY * gain * exposureTime * 1000. Thus the
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image is a linear ramp in the X and Y directions, with the gains in each direction being detector-specific parameters.
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Each subsquent acquisition increments each pixel value by gain*exposureTime*1000. Thus if gain=1 and exposureTime=.001
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second then the pixels are incremented by 1. If the array is an unsigned 8 or 16 bit integer then the pixels
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will overflow and wrap around to 0 after some period of time. This gives the appearance of bands that appear to move
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with time. The slope of the bands and their periodicity can be adjusted by changing the gains and exposure times.
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<P>
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The driver creates a thread that waits for a signal to start acquisition. When acquisition is started that thread
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computes new images and then calls back any registered plugins as follows:
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<PRE>
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/* Put the frame number and time stamp into the buffer */
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pImage->uniqueId = imageCounter;
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pImage->timeStamp = startTime.secPastEpoch + startTime.nsec / 1.e9;
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/* Call the NDArray callback */
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/* Must release the lock here, or we can get into a deadlock, because we can
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* block on the plugin lock, and the plugin can be calling us */
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epicsMutexUnlock(this->mutexId);
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asynPrint(this->pasynUser, ASYN_TRACE_FLOW,
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"%s:%s: calling imageData callback\n", driverName, functionName);
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doCallbacksGenericPointer(pImage, NDArrayData, addr);
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epicsMutexLock(this->mutexId);
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</PRE>
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The simulation driver-specific parameters are the following:
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<P>
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<TABLE style="TEXT-ALIGN: left" cellSpacing=2 cellPadding=2 border=1>
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<TBODY>
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<TR>
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<TD COLSPAN=7, ALIGN=CENTER><B>Parameter Definitions in simDetector.cpp and EPICS Record Definitions in simDetector.template</B></TD>
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</TR>
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<TR>
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<TH>Enum name</TH>
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<TH>asyn interface</TH>
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<TH>Access</TH>
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<TH>Description</TH>
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<TH>drvUser string</TH>
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<TH>EPICS record name</TH>
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<TH>EPICS record type</TH>
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</TR>
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<TR>
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<TD>SimGainX</TD>
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<TD>asynFloat64</TD>
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<TD>r/w</TD>
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<TD>Gain in the X direction</TD>
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<TD>SIM_GAINX</TD>
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<TD>$(P)$(R)GainX<BR>$(P)$(R)GainX_RBV</TD>
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<TD>ao<BR>ai</TD>
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</TR>
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<TR>
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<TD>SimGainY</TD>
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<TD>asynFloat64</TD>
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<TD>r/w</TD>
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<TD>Gain in the Y direction</TD>
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<TD>SIM_GAINY</TD>
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<TD>$(P)$(R)GainY<BR>$(P)$(R)GainY_RBV</TD>
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<TD>ao<BR>ai</TD>
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</TR>
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<TR>
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<TD>SimResetImage</TD>
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<TD>asynInt32</TD>
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<TD>r/w</TD>
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<TD>Reset image back to initial conditions when 1.</TD>
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<TD>RESET_IMAGE</TD>
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<TD>$(P)$(R)Reset<BR>$(P)$(R)Reset_RBV</TD>
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<TD>longout<BR>longin</TD>
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</TR>
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</TBODY>
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</TABLE>
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<P>
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The following is the MEDM screen ADBase.adl connected to a simulation detector.
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<P>
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<CENTER><IMG src="ADBase_sim.png"></CENTER>
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<P>
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The following is the MEDM screen that provides access to the specific parameters for the simulation detector.
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<P>
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<CENTER><IMG src="simDetector.png"></CENTER>
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<P>
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<P>
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The following is an IDL epics_ad_display screen using image_display (discussed below) illustrating the simulation detector images.
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<P>
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<CENTER><IMG src="simDetector_image_display.png"></CENTER>
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</BODY>
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</HTML>
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