class simDetector : public ADDriver {
public:
simDetector(const char *portName, int maxSizeX, int maxSizeY, NDDataType_t dataType,
int maxBuffers, size_t maxMemory);
/* These are the methods that we override from ADDriver */
virtual asynStatus writeInt32(asynUser *pasynUser, epicsInt32 value);
virtual asynStatus writeFloat64(asynUser *pasynUser, epicsFloat64 value);
virtual asynStatus drvUserCreate(asynUser *pasynUser, const char *drvInfo,
const char **pptypeName, size_t *psize);
void report(FILE *fp, int details);
The portName, maxBuffers, and maxMemory arguments are passed to the ADDriver base class constructor. The maxSizeX, maxSizeY, and
dataType arguments are specific to the simulation driver, controlling the maximum image size and initial data type of the
computed images. The writeInt32 and writeFloat64 methods override those in the base class. The driver takes action
when new parameters are passed via those interfaces. For example, the ADAcquire parameter (on the asynInt32 interface) is
used to turn acquisition (i.e. computing new images) on and off.
The simulation driver initially sets the image[i, j] = i*gainX + j*gainY * gain * exposureTime * 1000. Thus the image is a linear ramp in the X and Y directions, with the gains in each direction being detector-specific parameters. Each subsquent acquisition increments each pixel value by gain*exposureTime*1000. Thus if gain=1 and exposureTime=.001 second then the pixels are incremented by 1. If the array is an unsigned 8 or 16 bit integer then the pixels will overflow and wrap around to 0 after some period of time. This gives the appearance of bands that appear to move with time. The slope of the bands and their periodicity can be adjusted by changing the gains and exposure times.
The driver creates a thread that waits for a signal to start acquisition. When acquisition is started that thread computes new images and then calls back any registered plugins as follows:
/* Put the frame number and time stamp into the buffer */
pImage->uniqueId = imageCounter;
pImage->timeStamp = startTime.secPastEpoch + startTime.nsec / 1.e9;
/* Call the NDArray callback */
/* Must release the lock here, or we can get into a deadlock, because we can
* block on the plugin lock, and the plugin can be calling us */
epicsMutexUnlock(this->mutexId);
asynPrint(this->pasynUser, ASYN_TRACE_FLOW,
"%s:%s: calling imageData callback\n", driverName, functionName);
doCallbacksGenericPointer(pImage, NDArrayData, addr);
epicsMutexLock(this->mutexId);
The simulation driver-specific parameters are the following:
| Parameter Definitions in simDetector.cpp and EPICS Record Definitions in simDetector.template | ||||||
| Enum name | asyn interface | Access | Description | drvUser string | EPICS record name | EPICS record type |
|---|---|---|---|---|---|---|
| SimGainX | asynFloat64 | r/w | Gain in the X direction | SIM_GAINX | $(P)$(R)GainX $(P)$(R)GainX_RBV |
ao ai |
| SimGainY | asynFloat64 | r/w | Gain in the Y direction | SIM_GAINY | $(P)$(R)GainY $(P)$(R)GainY_RBV |
ao ai |
| SimResetImage | asynInt32 | r/w | Reset image back to initial conditions when 1. | RESET_IMAGE | $(P)$(R)Reset $(P)$(R)Reset_RBV |
longout longin |
The following is the MEDM screen ADBase.adl connected to a simulation detector.
The following is the MEDM screen that provides access to the specific parameters for the simulation detector.
The following is an IDL epics_ad_display screen using image_display (discussed below) illustrating the simulation detector images.
