Detector
Definitions of the set of detector hardware available. The file contains a JSON structure listing a set of fields that correspond to detector instances. The field name defines the detector name and the field value is another JSON structure declaring the configuration parameters. Note that Pixelator expects detectors that measure multiple values for each scan point (e.g. area detector) to also return a single value summarizing the measurement at each scan point.
active::
Integer value that defines if the detector should be used (value of 1) or ignored (value of 0).
Default: 0
type::
String value that identifies which hardware interface will handle the detector behaviour. The set of allowed values is listed near the beginning of Detector.h, for example:
enum Type { Base, Counter, Analog, Interferometer, Orchestra, OrocosPosition, OrocosSampler, Epics, Tcp, Zmq, PandAPos };
subType::
String value that defines how the detector. Only current usage is "time" for a "Base"-type detector that reports the linux epoch (clock value in terms of seconds since 1970).
Default: empty string
nexus_name::
String value defines the label string to be used in NeXus files, since these must conform to a specific naming scheme.
Default: detector name string
unit::
String value that defines the unit of the physical quantity being measured by the detector.
Default: empty string
hardwareUnitFactor::
Double value that defines conversion factor between values used by the controller and by Pixelator.
Default: 1.0
hardwareUnitOffset::
Double value that defines offset between values used by the controller and by Pixelator.
Default: 0.0
autoRecord::
Boolean value that defines if the detector is to be silently (no selection option present to the user) recorded in the /entry*/instrument/ section of the nexus file.
Default: false
monitor::
Boolean value that defines if the detector is to be treated as a monitor and recorded in the NeXus file as an NXmonitor.
Default: false
asynchronous::
Boolean value that indicates that a detector communicates the measured values asynchronously.
Default: false
detailedDataDimensions::
Array that defines the size of the size and shape (per scan point) of the extra data_detail values to be recorded in /entry*/instrument/detector/data_detail, alongside the standard detector data. When this optional property is not defined, no data_detail dataset is recorded. For example, a declaration of "detailedDataDimensions" : [2], would result in a data_detail dataset array of size [N,2], where N is the number of scan points.
Further configuration parameters are type-dependent.
Counter
devicePath::
OBSOLETE: Use deviceName instead. String value that defines the filesystem address of the device. May be used together with subdevice and channel. Default: empty string
deviceName::
String value that defines the filesystem address of the device in the /sys/ directory. May be used together with subdevice and channel. Default: empty string.
subdevice::
Integer value that defines part of a device address. May be used together with deviceName and channel.
Default: 0
clockSource::
Integer value that defines the address of the clock used to define the counting time intervals.
Default: 0
Analog
devicePath::
OBSOLETE: Use deviceName instead. String value that defines the filesystem address of the device. May be used together with subdevice and channel. Default: empty string
deviceName::
String value that defines the filesystem address of the device in the /sys/ directory. May be used together with subdevice and channel. Default: empty string.
subdevice::
Integer value that defines part of a device address. May be used together with deviceName and channel.
Default: 0
channel::
Integer value that defines part of a device address. Used together with deviceName and subdevice.
Default: 0
OrchestraDetector
controller::
String value that defines the controller that handles the detector.
OrocosPositionDetector
controller::
String value that defines the controller that handles the detector.
axis::
Integer value that defines which axis the "Interferometer" type detector measures along.
Default: 0
OrocosSampler
No further configuration options.
EpicsDetector
Simple, single-valued EPICS detectors only need to provide a channel name, for example:
"voltage" : {
"active" : 1,
"type" : "Epics",
"channel": "X07DA-ES1-USER:AI0",
},
An Epics type detector will cause Pixelator to wait for a response from EPICS at each scan point. An alternative is to configure a readOnly positioner with the orchestraDetector parameter, which will sample the most recent value of the EPICS channel without waiting for anything.
However, detectors that provide multiple values, e.g. area detectors, tend to also have significant read-out times and so require a bit more work to coordinate. Communication of the dwell time, pixel/scan-point index, triggering and file path/names can all be communicated via EPICS channels.
channel::
String value that defines the EPICS channel that the detector will source data from.
Default: empty string
channelDetails::
String value that defines the EPICS channel where Pixelator should expect to read the data_detail values.
Default: empty string
channelSetTime::
String value that defines (for an "Epics" detector) the EPICS channel where Pixelator provides the dwell time of the current scan point. This is commonly used for the exposure setting of an area detector. The value pushed to the EPICS channel is calculated by T×hardwareTimeFactor - hardwareTimeOffset, where T is the dwell time in ms used by Pixelator.
Default: empty string
channelStart::
String value that defines the EPICS channel that Pixelator should use to communicate a trigger for the detector to begin a measurement. Pixelator will set this channel to 1 when it wants to trigger the detector and then will monitor the channel for a change in value, upon which Pixelator will move the instrument to the next scan point. (i.e. the detector should change the channel value to indicate it has finished the measurement.)
Default: empty string
channelStatus::
Default: empty string
writeStatus::
Default: empty string
channelTrigger::
Default: empty string
channelCtr::
String value that defines the EPICS channel where Pixelator provides the index of the current scan point (i.e. an integer value that starts at 0 and increases with each scan point).
Default: empty string
channelFilename::
String value that defines the EPICS channel where Pixelator provides the file name where the detector should record data during the scan. This is for cases where the detector sends the full data directly to the file and only the summary data is sent to Pixelator.
Default: empty string
channelFilepath::
String value that defines the EPICS channel where Pixelator provides the file path where the detector should record data during the scan. To be used together with channelFilename.
Default: empty string
filepathBase::
Default: empty string
beginOfScanScript::
Default: empty string
hardwareTimeFactor::
Double value that defines the factor to convert the dwell time (ms) used by Pixelator to the dwell time value to be provided to the setTimeChannel EPICS channel.
Default: 1.0
hardwareTimeOffset::
Double value that defines the offset to convert the dwell time (ms) used by Pixelator to the dwell time value to be provided to the setTimeChannel EPICS channel.
Default: 0.0
multiTigger::
Default: 0
multiTiggerDelay::
Default: 0.0
getDataTimeout::
Double value that defines the number of seconds to wait for data to be received before moving on to the next scan point. Data that is not received is written as NaN in data file.
Default: 0.15
details::
Integer value that defines the length of the data array (always 1D) that will be returned by an "Epics" detector. Note that Pixelator requires detectors to additionally return a summary of the data array as a single value per scan point.
Default: 0
ZmqDetector
zmqPublisher::
String value that defines the ZMQ network address and port that Pixelator should subscribe to in order to receive the detector data. For example "tcp://x07da-qutag-1.psi.ch:5563".
Default: empty string
zmqRequester::
String value that defines the ZMQ network address and port that Pixelator should use to communicate measurement parameters and scheduling details with the detector. For example "tcp://x07da-qutag-1.psi.ch:5564". The current implementation (11.11.2022) does not actually use the requester port for anything, but a feature set similar to that of the Epics type detector is planned where communication will be performed over this ZMQ requester port.
Default: empty string
getDataTimeout::
Double value that defines the number of seconds to wait for data to be received before moving on to the next scan point. Data that is not received is written as NaN in data file.
Default: 0.15
details::
Integer value that defines the length of the data array (always 1D) that will be returned by the detector. Note that Pixelator requires detectors to additionally return a summary of the data array as a single value per scan point.
Default: 0
PandAPositionDetector
controller::
String value that defines the controller that handles the detector.
axis::
Integer value that defines which axis the "Interferometer" type detector measures along.
Default: 0