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Added new plots, finished conversion from old pilatusROI documentation

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git-svn-id: https://subversion.xor.aps.anl.gov/synApps/areaDetector/trunk@8038 dc6c5ff5-0b8b-c028-a01f-ffb33f00fc8b
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rivers
2008-12-11 23:12:04 +00:00
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documentation/pilatusDoc.html
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@@ -7,7 +7,7 @@
<h1>
areaDetector Pilatus driver</h1>
<h2>
September 21, 2008</h2>
December 11, 2008</h2>
<h2>
Mark Rivers</h2>
<h2>
@@ -97,7 +97,7 @@
<td>
In External Enable mode this value is not used by camserver. However, it should
be set larger than the maximum time exposure time from the external source, so that
pilatusROI.st can estimate how long to wait for the data files to be created before
the driver can estimate how long to wait for the data files to be created before
timing out.</td>
</tr>
<tr>
@@ -162,8 +162,7 @@
using the algorithm described for ADFileTemplate under <a href="areaDetectorDoc.html#ADStdDriverParams">
File Saving Parameters in ADStdDriverParams</a> is used as a basename. The following
examples show the interpretation of the basename.
<pre>
Basename Files produced
<pre>Basename Files produced
test6.tif test6_00000.tif, test6_00001.tif, ...
test6_.tif test6_00000.tif, test6_00001.tif, ...
@@ -186,7 +185,7 @@ test6_2_0035.tif test6_2_0035.tif, test6_2_0036.tif, ...
<h2 id="Driver_parameters" style="text-align: left">
Pilatus specific parameters</h2>
<p>
The Pilatus driver implements the following parameters in addition to those in ADStdDriverParams.h:.
The Pilatus driver implements the following parameters in addition to those in ADStdDriverParams.h:.
Note that to reduce the width of this table the enum names have been split into
2 lines, but these are just a single name, for example <code>PilatusDelayTime</code>.
</p>
@@ -214,7 +213,8 @@ test6_2_0035.tif test6_2_0035.tif, test6_2_0036.tif, ...
</tr>
<tr>
<td>
Pilatus<br/>DelayTime</td>
Pilatus<br />
DelayTime</td>
<td>
asynFloat64</td>
<td>
@@ -231,7 +231,8 @@ test6_2_0035.tif test6_2_0035.tif, test6_2_0036.tif, ...
</tr>
<tr>
<td>
Pilatus<br/>Threshold</td>
Pilatus<br />
Threshold</td>
<td>
asynFloat64</td>
<td>
@@ -271,7 +272,8 @@ test6_2_0035.tif test6_2_0035.tif, test6_2_0036.tif, ...
</tr>
<tr>
<td>
Pilatus<br/>Armed</td>
Pilatus<br />
Armed</td>
<td>
asynInt32</td>
<td>
@@ -290,7 +292,8 @@ test6_2_0035.tif test6_2_0035.tif, test6_2_0036.tif, ...
</tr>
<tr>
<td>
Pilatus<br/>TiffTimeout</td>
Pilatus<br />
TiffTimeout</td>
<td>
asynFloat64</td>
<td>
@@ -310,7 +313,8 @@ test6_2_0035.tif test6_2_0035.tif, test6_2_0036.tif, ...
</tr>
<tr>
<td>
Pilatus<br/>BadPixelFile</td>
Pilatus<br />
BadPixelFile</td>
<td>
asynOctet</td>
<td>
@@ -320,8 +324,7 @@ test6_2_0035.tif test6_2_0035.tif, test6_2_0036.tif, ...
a valid bad pixel file then no bad pixel mapping is performed. The bad pixel map
is used before making the NDArray callbacks. It does not modify the data in the
files that camserver writes. This is a simple ASCII file with the following format:
<pre>
badX1,badY1 replacementX1,replacementY1
<pre>badX1,badY1 replacementX1,replacementY1
badX2,badY2 replacementX2,replacementY2
...
</pre>
@@ -350,7 +353,8 @@ badX2,badY2 replacementX2,replacementY2
</tr>
<tr>
<td>
Pilatus<br/>NumBadPixels</td>
Pilatus<br />
NumBadPixels</td>
<td>
asynInt32</td>
<td>
@@ -367,7 +371,8 @@ badX2,badY2 replacementX2,replacementY2
</tr>
<tr>
<td>
Pilatus<br/>FlatFieldFile</td>
Pilatus<br />
FlatFieldFile</td>
<td>
asynOctet</td>
<td>
@@ -379,12 +384,11 @@ badX2,badY2 replacementX2,replacementY2
for spatial non-uniformity in the response of the detector. It should be collected
with a spatially uniform intensity on the detector at roughly the same energy as
the measurements being corrected. When the flat field file is read, the average
pixel value (averageFlatField) is computed using all pixels with intensities > PilatusMinFlatField.
All pixels with intensity < PilatusMinFlatField in the flat field are replaced with
averageFlatField. When images are collected before the NDArray callbacks are performed
the following per-pixel correction is applied:
<pre>
ImageData[i] =
pixel value (averageFlatField) is computed using all pixels with intensities &gt
PilatusMinFlatField. All pixels with intensity &lt PilatusMinFlatField in the flat
field are replaced with averageFlatField. When images are collected before the NDArray
callbacks are performed the following per-pixel correction is applied:
<pre>ImageData[i] =
(averageFlatField *
ImageData[i])/flatField[i];
</pre>
@@ -398,7 +402,8 @@ ImageData[i] =
</tr>
<tr>
<td>
Pilatus<br/>MinFlatField</td>
Pilatus<br />
MinFlatField</td>
<td>
asynInt32</td>
<td>
@@ -417,7 +422,8 @@ ImageData[i] =
</tr>
<tr>
<td>
Pilatus<br/>FlatFieldValid</td>
Pilatus<br />
FlatFieldValid</td>
<td>
asynInt32</td>
<td>
@@ -626,10 +632,10 @@ create_monitor_set("auto_settings.req", 30,"P=13PIL1:,D=cam1:")
NDROI8.adl</h3>
<img alt="NDROI8.png" src="NDROI8.png" /></div>
<p>
<code>mca.adl</code> can be used to plot the net or total counts in an ROI when
NImages>1. In this example the plot is the net counts in ROI 1 as the diffractometer
chi was scanned +- 1 degree with 1000 points at .02 seconds/point. This was done
with the SPEC command
<code>mca.adl or mca_small.adl</code> can be used to plot the net or total counts
in an ROI when NImages>1. In this example the plot is the net counts in ROI 1 as
the diffractometer chi was scanned +- 1 degree with 1000 points at .02 seconds/point.
This was done with the SPEC command
</p>
<pre>lup chi -1 1 1000 .02
</pre>
@@ -638,10 +644,10 @@ create_monitor_set("auto_settings.req", 30,"P=13PIL1:,D=cam1:")
motor scan with the Newport XPS putting out pulses every .02 seconds. These pulses
triggered the Pilatus in External Enable mode. The Pilatus driver read each TIFF
file as it was created and updated this plot every 0.2 seconds. The total time to
collect this scan with 1000 images was 20 seconds.</p>
collect this scan with 1000 images was 20.8 seconds.</p>
<div style="text-align: center">
<h3 style="text-align: center">
mca.adl</h3>
mca_small.adl</h3>
<img alt="pilatusMCA.png" src="pilatusMCA.png" style="text-align: left" /></div>
<p>
<code>scan_more.adl</code> is used to define a scan. In this example the sscan record
@@ -650,24 +656,24 @@ create_monitor_set("auto_settings.req", 30,"P=13PIL1:,D=cam1:")
<div style="text-align: center">
<h3>
scan_more.adl</h3>
<img alt="pilatusROI_scan_more.png" src="pilatus_scan_more.png" /></div>
<img alt="pilatusThresholdScanSetup.png" src="pilatusThresholdScanSetup.png" /></div>
<p>
<code>scanDetPlot.adl</code> is used to plot the results of a scan after it is complete.
In this example the total counts in ROI 2 are plotted as a function of the ThresholdEnergy
In this example the total counts in ROI 1 are plotted as a function of the ThresholdEnergy
as it was scanned from 3000 to 10000 eV in 250 eV steps. The source was Fe55, and
the cut-off is at 6 keV, as expected for the Mn Ka and Mn Kb x-rays that this source
produces.</p>
<div style="text-align: center">
<h3>
scanDetPlot.adl</h3>
<img alt="pilatus_scan_plot.png" src="pilatus_scan_plot.png" /></div>
<img alt="pilatusThresholdScanPlot.png" src="pilatusThresholdScanPlot.png" /></div>
<p>
<code>asynRecord.adl</code> is used to control the debugging information printed
by the asyn TCP/IP driver (asynTraceIODriver) and the SNL program (asynTraceIODevice).</p>
by the asyn TCP/IP driver for camserver (asynTraceIODriver).</p>
<div style="text-align: center">
<h3>
asynRecord.adl</h3>
<img alt="pilatusAsynRecord.png" src="pilatusAsynRecord.png" /></div>
<img alt="pilatusAsyn.png" src="pilatusAsyn.png" /></div>
<p>
<code>asynOctet.adl</code> can be used to send any command to camserver and display
the response. It can be loaded from the More menu in asynRecord.adl above.</p>
@@ -684,9 +690,13 @@ create_monitor_set("auto_settings.req", 30,"P=13PIL1:,D=cam1:")
in both traditional step-scanning mode, as well as in <a href="http://cars.uchicago.edu/software/epics/trajectoryScan.html">
trajectory scanning</a> mode. Here are some snippets from the SPEC macros for
the Pilatus. We can supply the source files on request.</p>
<pre># need some more globals (kludge)
global PILATUS_ROI_PV
global PILATUS_imgPATH_PV
<pre> # need some more globals (kludge)
global PILATUS_ROI_PV
global PILATUS_ROI_ARRAY_PV
global PILATUS_ROI_ARRAY_START_PV
global PILATUS_ROI_ARRAY_NUSE_PV
global PILATUS_ROI_ARRAY_ACQ_PV
global PILATUS_IMGPATH_PV
global PILATUS_FNAME_PV
global PILATUS_FILENUMBER_PV
global PILATUS_FILEFORMAT_PV
@@ -695,60 +705,119 @@ global PILATUS_NFRAME_PV
global PILATUS_EXPPRD_PV
global PILATUS_NEXPFRM_PV
global PILATUS_ACQ_PV
global PILATUS_ARMED_PV
global PILATUS_ABORT_PV
global PILATUS_ACQMODE_PV
global PILATUS_READOUT_TIME
global PILATUS_ROI_0_MinX_PV
global PILATUS_ROI_0_SizeX_PV
global PILATUS_ROI_0_MinY_PV
global PILATUS_ROI_0_SizeY_PV
###############################################################
def _setup_img '{
local j, str
# PILATUS_PREFIX should be detector aquisition pv (GSE-PILATUS1:)
...
# PILATUS_PREFIX detector name i.e. (GSE-PILATUS1:)
if ( PILATUS_PREFIX == "") PILATUS_PREFIX = "GSE-PILATUS1:"
PILATUS_PREFIX = getval("Enter PILATUS pv prefix",PILATUS_PREFIX)
PILATUS_PREFIX = getsval("Enter PILATUS detector name i.e. GSE-PILATUS1:",PILATUS_PREFIX)
# rois pvs
PILATUS_ROI_PV = PILATUS_PREFIX "ROI1NetCounts"
PILATUS_imgPATH_PV = PILATUS_PREFIX "FilePath"
PILATUS_FNAME_PV = PILATUS_PREFIX "Filename"
PILATUS_FILENUMBER_PV = PILATUS_PREFIX "FileNumber"
PILATUS_FILEFORMAT_PV = PILATUS_PREFIX "FileFormat"
PILATUS_EXPSRTM_PV = PILATUS_PREFIX "ExposureTime"
PILATUS_NFRAME_PV = PILATUS_PREFIX "NImages"
PILATUS_EXPPRD_PV = PILATUS_PREFIX "ExposurePeriod"
PILATUS_NEXPFRM_PV = PILATUS_PREFIX "NExposures"
PILATUS_ACQ_PV = PILATUS_PREFIX "Acquire"
PILATUS_ACQMODE_PV = PILATUS_PREFIX "AcquireMode"
# PILATUS_DET_PREFIX is the pv used by areaDetector to identify a specific detector.
# When only one detector is used it is usally (cam1:)
if ( PILATUS_DET_PREFIX == "") PILATUS_DET_PREFIX = "cam1:"
PILATUS_DET_PREFIX = getsval("Enter PILATUS specific detector name i.e. cam1:",PILATUS_DET_PREFIX)
# PILATUS_ROI_PREFIX is the pv used by areaDetector to identify a specific a ROI plugin.
# When only one ROI plugin is used it is usally (ROI1:)
if ( PILATUS_ROI_PREFIX == "") PILATUS_DET_PREFIX = "ROI1:"
PILATUS_ROI_PREFIX = getsval("Enter PILATUS ROI plugin name i.e. ROI1:",PILATUS_ROI_PREFIX)
if (PILATUS_MOUNT == "") PILATUS_MOUNT = "cars5/Data"
PILATUS_MOUNT = getsval("Enter mount point relative to camserver home directory",PILATUS_MOUNT)
if (PILATUS_SPEC_MOUNT == "") PILATUS_SPEC_MOUNT = "cars5/Data"
PILATUS_SPEC_MOUNT = getsval("Enter mount point relative to spec home directory",PILATUS_SPEC_MOUNT)
...
PILATUS_ROI_PV = PILATUS_PREFIX PILATUS_ROI_PREFIX "0:Net_RBV"
PILATUS_ROI_ARRAY_PV = PILATUS_PREFIX PILATUS_ROI_PREFIX "0:NetArray"
PILATUS_ROI_ARRAY_START_PV = PILATUS_PREFIX PILATUS_ROI_PREFIX "0:NetArrayEraseStart"
PILATUS_ROI_ARRAY_NUSE_PV = PILATUS_PREFIX PILATUS_ROI_PREFIX "0:NetArray.NUSE"
PILATUS_ROI_ARRAY_ACQ_PV = PILATUS_PREFIX PILATUS_ROI_PREFIX "0:NetArray.ACQG"
PILATUS_IMGPATH_PV = PILATUS_PREFIX PILATUS_DET_PREFIX "FilePath"
PILATUS_FNAME_PV = PILATUS_PREFIX PILATUS_DET_PREFIX "FileName"
PILATUS_FILENUMBER_PV = PILATUS_PREFIX PILATUS_DET_PREFIX "FileNumber"
PILATUS_FILEFORMAT_PV = PILATUS_PREFIX PILATUS_DET_PREFIX "FileTemplate"
PILATUS_EXPSRTM_PV = PILATUS_PREFIX PILATUS_DET_PREFIX "AcquireTime"
PILATUS_NFRAME_PV = PILATUS_PREFIX PILATUS_DET_PREFIX "NumImages"
PILATUS_EXPPRD_PV = PILATUS_PREFIX PILATUS_DET_PREFIX "AcquirePeriod"
PILATUS_NEXPFRM_PV = PILATUS_PREFIX PILATUS_DET_PREFIX "NumExposures"
PILATUS_ACQ_PV = PILATUS_PREFIX PILATUS_DET_PREFIX "Acquire"
PILATUS_ARMED_PV = PILATUS_PREFIX PILATUS_DET_PREFIX "Armed"
PILATUS_ABORT_PV = PILATUS_PREFIX PILATUS_DET_PREFIX "Acquire"
PILATUS_ACQMODE_PV = PILATUS_PREFIX PILATUS_DET_PREFIX "TriggerMode"
PILATUS_THRESHOLD_PV = PILATUS_PREFIX PILATUS_DET_PREFIX "ThresholdEnergy"
PILATUS_ROI_0_MinX_PV = PILATUS_PREFIX PILATUS_ROI_PREFIX "0:MinX"
PILATUS_ROI_0_SizeX_PV = PILATUS_PREFIX PILATUS_ROI_PREFIX "0:SizeX"
PILATUS_ROI_0_MinY_PV = PILATUS_PREFIX PILATUS_ROI_PREFIX "0:MinY"
PILATUS_ROI_0_SizeY_PV = PILATUS_PREFIX PILATUS_ROI_PREFIX "0:SizeY"
PILATUS_ROI_0_BgdWidth_PV = PILATUS_PREFIX PILATUS_ROI_PREFIX "0:BgdWidth"
...
def epics_pilatus_count '{
...
# write to data base fields
# Need to convert path from string to byte array
# Note: we use the "wait" parameter in epics_put here (new to spec5.7.02) so that
# it uses ca_put_callback, to know that all PVs have been processed
# before we start counting. Use 1 second timeout, will actually be
# much faster than this unless something is wrong.
array _temp[256]
_temp = PILATUS_IMAGE_DIR
# Do not change path for now
#epics_put(PILATUS_imgPATH_PV,_temp, 1)
epics_put(PILATUS_FNAME_PV,img_fname, 1)
# Call macro that creates and set the Pilatus path and filename
img_full_filename
# Setup exposure time, collection mode and number of frames
epics_put(PILATUS_FILENUMBER_PV,NPTS, 1)
epics_put(PILATUS_FILEFORMAT_PV,_fileformat, 1)
epics_put(sc_prtm_pv,cnt_time_val, 1)
epics_put(PILATUS_EXPSRTM_PV,cnt_time_val, 1)
epics_put(PILATUS_ACQMODE_PV,0, 1) # Internal trigger
epics_put(PILATUS_NFRAME_PV, 1, 1)
epics_put(PILATUS_ACQMODE_PV,0, 1) # Internal trigger
epics_put(PILATUS_EXPSRTM_PV,cnt_time_val, 1)
epics_put(PILATUS_NEXPFRM_PV, 1, 1)
...
# hit the triggers
epics_put(PILATUS_ACQ_PV,1)
epics_put(sc_cnt_pv,1)
# wait for scaler and Pilatus AQG to finish
status = 1
sc_done = FALSE
img_done = FALSE
data_done = FALSE
while(status){
# is the scalar done
if (epics_get(sc_cnt_pv)=="Done"){
sc_done = TRUE;
#p "scaler done"
}
# is the pilatus done
if (epics_get(PILATUS_ACQ_PV) == "Done"){
img_done = TRUE;
#p "image collection done"
}
if( (sc_done==TRUE) && (img_done==TRUE)) break;
sleep(0.01)
}
# use the get_counts routine to read the scalers
# note get_counts also calls user_getcounts
# thats where the rois get read.
get_counts
}'
def user_getcounts '{
local pv_roi, j, pv
...
# using image_count routine
# using image_count routine
} else if ( EPICS_COUNT == 4 ) {
S[iroi] = 0
S[iroi] = epics_get(PILATUS_ROI_PV)
</pre>
<h2 id="Performance measurements">
Performance measurements</h2>
@@ -761,7 +830,7 @@ def user_getcounts '{
was measured using the EPICS camonitor program. It printed the time when acquisition
was started (Acquire changed to Acquire=1) and when acquisition was complete (Acquire
changed to Done=0). The time was 10.022 seconds. This includes the time for camserver
to save all 1000 images to disk (366 MB), and for pilatusROI to read each file,
to save all 1000 images to disk (366 MB), and for the driver to read each file,
correct the bad pixels and flat field, compute the ROIs, and post the ROIs to EPICS.
It also posted all of the images to EPICS. The total additional time was less than
0.03 seconds for all 1000 images.</li>
@@ -772,7 +841,7 @@ def user_getcounts '{
collect each file. If there were no overhead then time to collect this series should
be exactly 10.0 seconds. The actual time measured using the EPICS camonitor program
was 45.514 seconds. The overhead is thus 35.514 seconds, or 35 ms per point. In
this single-frame mode pilatusROI is thus able to collect >20 images/second. For
this single-frame mode the driver is thus able to collect >20 images/second. For
comparison, another measurement was done using the same EPICS sscan record, but
using a Joerger VSC16 scaler as the detector trigger and detector. The preset time
was also .01 seconds. The elapsed time for a 1000 point scan was 16.068 seconds,
@@ -781,41 +850,38 @@ def user_getcounts '{
1000 points using <a href="http://cars.uchicago.edu/software/epics/trajectoryScan.html">
trajectory scanning</a> mode with the Newport XPS motor controller. The following
SPEC command was used:
<pre> lup chi -2 2 1000 .015
<pre> lup chi -1 1 1000 .02
</pre>
This tells SPEC to do a relative scan of the chi axis from -2 degrees to +2 degrees
with 1000 points at .015 seconds/point. On our kappa diffractometer this entails
a coordinated motion of the phi, kappa and omega axes. The EPICS trajectory scanning
software downloads the non-linear trajectory that SPEC computes into the XPS controller,
which executes it. As the motors are moving the XPS outputs synchronization pulses
at the period of the collection time, .015 seconds in this case. These pulses are
stretched (see <a href="#Hardware notes">Hardware notes</a> below) and used as the
external input to the Pilatus. The time to execute this scan should be 15.0 seconds.
The actual time was 16.3 seconds, measured using camonitor on the Acquire PV. Again,
this includes the time for camserver to save all 1000 images to disk (366 MB), and
for pilatusROI to read each file, correct the bad pixels and flat field, compute
the ROIs, and post the ROIs to EPICS. It also posted the images to EPICS at 1Hz
(15 images total). The total additional time was less than 1.3 seconds for all 1000
images. As soon as the acquisition was complete SPEC plotted the net counts in the
first ROI (containing the Bragg peak) as follows:
at the period of the collection time, .020 seconds in this case. These pulses are
used as the external trigger to the Pilatus. The time to execute this scan should
be 20.0 seconds. The actual time was 20.8 seconds, measured using camonitor on the
Acquire PV. Again, this includes the time for camserver to save all 1000 images
to disk (366 MB), and for the Pilatus driver to read each file, correct the bad
pixels and flat field, compute the ROIs, and post the ROIs to EPICS. It also posted
all of the images to EPICS. The total additional time was less than 0.8 seconds
for all 1000 images. As soon as the acquisition was complete SPEC plotted the net
counts in the first ROI (containing the Bragg peak) as follows:
<div style="text-align: center">
<h3>
1000 point SPEC scan with 15 ms per point collected in 16.3 seconds</h3>
<img alt="pilatusROI_spec.png" src="pilatus_spec.png" /></div>
1000 point SPEC scan with 20 ms per point collected in 20.8 seconds</h3>
<img alt="pilatusSPEC.png" src="pilatusSPEC.png" /></div>
<p>
</p>
For comparison this identical scan was executed in traditional step-scanning mode,
where the motors stopped at each point in the scan. The Pilatus was run in Internal
mode with NImages=1. The total time for the scan was 870 seconds (more than 14 minutes),
compared to 16.3 seconds in trajectory mode. Most of this overhead is the settling
time for the motors, with only a small fraction due to the Pilatus single-exposure
mode. The trajectory scanning mode is thus more than 50 times faster to execute
the identical SPEC scan.</li>
mode with NumImages=1. The total time for the scan was 870 seconds (more than 14
minutes), compared to 20.8 seconds in trajectory mode. Most of this overhead is
the settling time for the motors, with only a small fraction due to the Pilatus
single-exposure mode. The trajectory scanning mode is thus more than 50 times faster
to execute the identical SPEC scan.</li>
</ol>
<h2 id="Hardware notes" style="text-align: left">
&nbsp;</h2>
<h2 style="text-align: left">
Hardware notes</h2>
</h2>
<h3>
Trigger pulses</h3>
<p>
@@ -893,13 +959,13 @@ def user_getcounts '{
<h2 id="Restrictions">
Restrictions</h2>
<p>
The following are some current restrictions of the pilatusROI SNL program:</p>
The following are some current restrictions of the areaDetector Pilatus driver:</p>
<ul>
<li>Limited to TIFF file format. camserver can save files in other formats, but pilatusROI
can currently only read TIFF files. Furthermore, it has a very simple TIFF reader.
It does not read the TIFF tags at all, but simply assumes that there is a 4096 byte
header, followed by the 32-bit image data. The size of the image data is controlled
by the NXPixels and NYPixels PVs, which thus must be correctly set.</li>
<li>Limited to TIFF file format. camserver can save files in other formats, but the
driver can currently only read TIFF files. It uses the standard libtiff library
to read the files, so it should work on big or little endian machines, and should
work with uncompressed or compressed files. It has only been tested with uncompressed
files on a little-endian machine.</li>
<li>The EPICS IOC should be run on the same computer as camserver. This is not strictly
necessary, and places a small additional load on the CPU and network on that computer.
However, we have found that TIFF files are available to be read within 10ms after
@@ -910,24 +976,23 @@ def user_getcounts '{
file has been written before the IOC can read it. This is true even if the files
are being written to the computer that the IOC is running on! This 1 second delay
is often unacceptable for fast single-exposure scans, i.e. with NImages=1.</li>
<li>pilatusROI keeps retrying to read each TIFF file until the modification date of
the TIFF file is <i>after</i> the time that the exposure command was issued. If
it did not do this check then it could be reading and displaying old files that
<li>The Pilatus driver keeps retrying to read each TIFF file until the modification
date of the TIFF file is <i>after</i> the time that the acquisition was started.
If it did not do this check then it could be reading and displaying old files that
happen to have the same name as the current files being collected. This check requires
that the computer that is running the soft IOC must have its clock well synchronized
with the clock on the computer on which the files are being written (i.e. the computer
generating the file modification time). If the clocks are not synchronized then
the files may appear to be stale when they are not, and pilatusROI will time out.
pilatusROI actually tolerates up to 10 second clock skew betweeen the computers
the files may appear to be stale when they are not, and the driver will time out.
The driver actually tolerates up to 10 second clock skew betweeen the computers
but any more than this may lead to problems.</li>
<li>The Abort PV does not always work because camserver does not reliably implement
the "K" command to stop an exposure sequence. In particular with NImages>1 camserver
seems to often ignore the K command completely, even with exposure times/periods
as long as 10 seconds. With NImages=1 it does kill the exposure after a few seconds.</li>
<li>The following items are hardcoded in the SNL program. They can be changed before
compiling if necessary. Some could be changed to be EPICS PVs, so they could be
controlled at run-time, but others must be defined at compile time because of limitations
in the SNL semantics.
<li>Setting Acquire to 0 does not always stop acquisition immediately because camserver
does not reliably implement the "K" command to stop an exposure sequence. In particular
with NumImages>1 camserver seems to often ignore the K command completely, even
with exposure times/periods as long as 10 seconds. With NumImages=1 it does kill
the exposure after a few seconds.</li>
<li>The following items are hardcoded in the driver. They can be changed by compiling
if necessary.
<ul>
<li>MAX_MESSAGE_SIZE=256 The maximum size of message to/from camserver.</li>
<li>MAX_FILENAME_LEN=256 The maximum size of a complete file name including path and
@@ -935,9 +1000,6 @@ def user_getcounts '{
<li>FILE_READ_DELAY=.01 seconds. The time between polling to see if the TIFF file
exists or if it is the expected size.</li>
<li>MAX_BAD_PIXELS=100 The maximum number of bad pixels.</li>
<li>MAX_ROIS=32 The maximum number of ROIs</li>
<li>MAX_READ_ERRORS=3 The maximum number of TIFF file read errors before the SNL gives
up and aborts acquisition.</li>
</ul>
</li>
</ul>