This package provides an interface to NI-DAQmx--- National Instruments' driver for their data acquisition boards. Their entire C header file was ported using Clang.jl, and a rudimentary higher-level API is provided for ease of use.
Similar functionality for the Python language is provided by PyDAQmx.
NI-DAQmx Base is not supported, so you'll need a Windows box, and a National Instruments card of course.
First download and install NI-DAQmx version 18.6 ( or for julia v6, 17.1.0; or for Julia v5, 16.0.0; or for Julia v4, 15.1.1; or for Julia v3, 14.1.0, 14.0.0, or 9.6.0) from National Instruments. Then on the Julia command line:
]add NIDAQ
With no input arguments, the high-level getproperties function can
be used to query the system:
julia> using NIDAQ
julia> getproperties()
Dict{String,Tuple{Any,Bool}} with 7 entries:
"DevNames" => (SubString{String}["Dev1"],false)
"GlobalChans" => (SubString{String}[""],false)
"NIDAQMajorVersion" => (0x00000010,false)
"NIDAQMinorVersion" => (0x00000000,false)
"NIDAQUpdateVersion" => (0x00000000,false)
"Scales" => (SubString{String}[""],false)
"Tasks" => (SubString{String}[""],false)
Returned is a dictionary of tuples, the first member indicating the property value and the second a boolean indicating whether the former is mutable.
getproperties can also input a string containing the name of a data acquisition device:
julia> getproperties("Dev1")
Dict{String,Tuple{Any,Bool}} with 61 entries:
"AIBridgeRngs" => (Float64[],false)
"AICouplings" => (:Val_Transferred_From_Buffer,false)
"AICurrentIntExcitDiscreteVals" => (Float64[],false)
"AICurrentRngs" => (Float64[],false)
"AIDigFltrLowpassCutoffFreqDiscreteVals" => (Float64[],false)
"AIDigFltrLowpassCutoffFreqRangeVals" => (Float64[],false)
"AIFreqRngs" => (Float64[],false)
"AIGains" => (Float64[],false)
"AILowpassCutoffFreqDiscreteVals" => (Float64[],false)
"AILowpassCutoffFreqRangeVals" => (Float64[],false)
"AIMaxMultiChanRate" => (2.0e6,false)
"AIMaxSingleChanRate" => (2.0e6,false)
"AIMinRate" => (0.0232831,false)
"AIPhysicalChans" => (SubString{String}["Dev1/ai0","Dev1/ai1","Dev1/ai2",".
"AIResistanceRngs" => (Float64[],false)
"AISampModes" => (Symbol[:Val_FiniteSamps,:Val_ContSamps],false)
"AISupportedMeasTypes" => (Symbol[:Val_Current,:Val_Resistance,:Val_Strain_Gage.
"AITrigUsage" => (14,false)
"AIVoltageIntExcitDiscreteVals" => (Float64[],false)
"AIVoltageIntExcitRangeVals" => (Float64[],false)
"AIVoltageRngs" => ([-1.0,1.0,-2.0,2.0,-5.0,5.0,-10.0,10.0],false)
"AOCurrentRngs" => (Float64[],false)
"AOGains" => (Float64[],false)
"AOMaxRate" => (3.33333e6,false)
"AOMinRate" => (0.0232831,false)
"AOPhysicalChans" => (SubString{String}["Dev1/ao0","Dev1/ao1"],false)
"AOSampModes" => (Symbol[:Val_FiniteSamps,:Val_ContSamps],false)
"AOSupportedOutputTypes" => (Symbol[:Val_Voltage],false)
"AOTrigUsage" => (10,false)
"AOVoltageRngs" => ([-5.0,5.0,-10.0,10.0],false)
"AccessoryProductNums" => (UInt32[0x00000000],false)
"AccessoryProductTypes" => (SubString{String}[""],false)
"AccessorySerialNums" => (UInt32[0x00000000],false)
"BusType" => (:Val_USB,false)
"CIMaxSize" => (0x00000020,false)
"CIMaxTimebase" => (1.0e8,false)
"CIPhysicalChans" => (SubString{String}["Dev1/ctr0","Dev1/ctr1","Dev1/ctr2.
"CISampModes" => (Symbol[:Val_FiniteSamps,:Val_ContSamps],false)
"CISupportedMeasTypes" => (Symbol[:Val_CountEdges,:Val_Freq,:Val_Period,:Val_Tw.
"CITrigUsage" => (42,false)
"COMaxSize" => (0x00000020,false)
"COMaxTimebase" => (1.0e8,false)
"COPhysicalChans" => (SubString{String}["Dev1/ctr0","Dev1/ctr1","Dev1/ctr2.
"COSampModes" => (Symbol[:Val_FiniteSamps,:Val_ContSamps],false)
"COSupportedOutputTypes" => (Symbol[:Val_Pulse_Freq,:Val_Pulse_Ticks,:Val_Pulse_T.
"COTrigUsage" => (42,false)
"ChassisModuleDevNames" => (SubString{String}[""],false)
"DILines" => (SubString{String}["Dev1/port0/line0","Dev1/port0/lin.
"DIMaxRate" => (1.0e7,false)
"DIPorts" => (SubString{String}["Dev1/port0","Dev1/port1","Dev1/po.
"DITrigUsage" => (14,false)
"DOLines" => (SubString{String}["Dev1/port0/line0","Dev1/port0/lin.
"DOMaxRate" => (1.0e7,false)
"DOPorts" => (SubString{String}["Dev1/port0","Dev1/port1","Dev1/po.
"DOTrigUsage" => (10,false)
"NumDMAChans" => (0x00000000,false)
"ProductCategory" => (:Val_XSeriesDAQ,false)
"ProductNum" => (0x000075a1,false)
"ProductType" => (SubString{String}["USB-6366 (64 MS) (Mass Terminatio.
"SerialNum" => (0x01719e54,false)
"Terminals" => (SubString{String}["/Dev1/PFI0","/Dev1/PFI1","/Dev1/P.
One can index into the dictionary to get a list of channels:
julia> getproperties("Dev1")["AIPhysicalChans"]
(SubString{ASCIIString}["Dev1/ai0","Dev1/ai1","Dev1/ai2","Dev1/ai3","Dev1/ai4","Dev1/ai5","Dev1/ai6","Dev1/ai7"],false)
A bit simpler in this case though is to use another high-level function which returns just the string Array:
julia> analog_input_channels("Dev1")
8-element Array{String,1}:
"Dev1/ai0"
"Dev1/ai1"
"Dev1/ai2"
"Dev1/ai3"
"Dev1/ai4"
"Dev1/ai5"
"Dev1/ai6"
"Dev1/ai7"
To add, for example, analog input channels, use the high-level analog_input function:
julia> t = analog_input("Dev1/ai0:1")
NIDAQ.AITask(Ptr{Nothing} @0x0000000025d18600)
julia> typeof(t)
NIDAQ.AITask (constructor with 3 methods)
julia> supertype(NIDAQ.AITask)
NIDAQ.Task
Two channels were added above using the : notation. Additional
channels can be added later by inputing the returned Task:
julia> analog_input(t, "Dev1/ai2")
getproperties can also input a Task:
julia> getproperties(t)
Dict{String,Tuple{Any,Bool}} with 5 entries:
"Devices" => (SubString{String}["Dev1"],false)
"Channels" => (SubString{String}["Dev1/ai0","Dev1/ai1","Dev1/ai2"],false)
"Name" => (SubString{String}["_unnamedTask<0>"],false)
"NumChans" => (0x00000003,false)
"NumDevices" => (0x00000001,false)
as well as a string containing the name of the channel:
julia> getproperties(t, "Dev1/ai0")
Dict{String,Tuple{Any,Bool}} with 52 entries:
"AccelUnits" => (:Val_g,false)
"AutoZeroMode" => (:Val_None,false)
"BridgeUnits" => (:Val_VoltsPerVolt,false)
"ChanCalDesc" => (SubString{String}[""],false)
"ChanCalOperatorName" => (SubString{String}[""],false)
"ChanCalPolyForwardCoeff" => (Float64[],false)
"ChanCalPolyReverseCoeff" => (Float64[],false)
"ChanCalScaleType" => (:Val_Table,false)
"ChanCalTablePreScaledVals" => (Float64[],false)
"ChanCalTableScaledVals" => (Float64[],false)
"ChanCalVerifAcqVals" => (Float64[],false)
"ChanCalVerifRefVals" => (Float64[],false)
"Coupling" => (:Val_DC,false)
"CurrentACRMSUnits" => (:Val_Amps,false)
"CurrentUnits" => (:Val_Amps,false)
"CustomScaleName" => (SubString{String}[""],false)
"DataXferMech" => (:Val_ProgrammedIO,false)
"DataXferReqCond" => (:Val_OnBrdMemNotEmpty,false)
"DevScalingCoeff" => ([0.000102924,0.000312673,5.87393e-14,-3.31855e-19],false)
"EddyCurrentProxProbeUnits" => (:Val_Meters,false)
"ForceUnits" => (:Val_Newtons,false)
"FreqUnits" => (:Val_Hz,false)
"Gain" => (1.0,false)
"InputSrc" => (SubString{String}["_external_channel"],false)
"LVDTUnits" => (:Val_Meters,false)
"LossyLSBRemovalCompressedSampSize" => (0x00000010,false)
"Max" => (10.0,false)
"MeasType" => (:Val_Voltage,false)
"Min" => (-10.0,false)
"PressureUnits" => (:Val_PoundsPerSquareInch,false)
"RVDTUnits" => (:Val_Degrees,false)
"RawDataCompressionType" => (:Val_None,false)
"RawSampJustification" => (:Val_RightJustified,false)
"RawSampSize" => (0x00000010,false)
"ResistanceUnits" => (:Val_Ohms,false)
"Resolution" => (16.0,false)
"ResolutionUnits" => (:Val_Bits,false)
"RngHigh" => (10.0,false)
"RngLow" => (-10.0,false)
"SoundPressureUnits" => (:Val_Pascals,false)
"StrainGageCfg" => (:Val_FullBridgeI,false)
"StrainUnits" => (:Val_Strain,false)
"TempUnits" => (:Val_DegC,false)
"TermCfg" => (:Val_Diff,false)
"ThrmcplCJCVal" => (25.0,false)
"TorqueUnits" => (:Val_NewtonMeters,false)
"UsbXferReqCount" => (0x00000004,false)
"UsbXferReqSize" => (0x00008000,false)
"VelocityUnits" => (:Val_MetersPerSecond,false)
"VoltageACRMSUnits" => (:Val_Volts,false)
"VoltageUnits" => (:Val_Volts,false)
"VoltagedBRef" => (1.0,false)
Use setproperty! to change a mutable property:
julia> setproperty!(t, "Dev1/ai0", "Max", 5.0)
Once everything is configured, get some data using the read function:
julia> start(t)
julia> read(t, 10)
10x3 Array{Float64,2}:
1.52407 -0.448835 0.381075
1.37546 -0.213537 0.305847
1.2363 -0.0268698 0.262826
1.109 0.118619 0.243117
0.995797 0.2311 0.240073
0.896695 0.315782 0.248004
0.811452 0.378752 0.262746
0.739429 0.424257 0.281893
0.679263 0.456223 0.302402
0.629672 0.477774 0.323473
julia> stop(t)
julia> clear(t)
read can also return Int16, Int32, UInt16, and UInt32 by specifying
those types as an additional argument:
julia> read(t, 10, Int16)
10×3 Array{Int16,2}:
-12619 -5351 -13973
-12618 -5350 -13973
-12620 -5350 -13973
-12619 -5350 -13974
-12618 -5351 -13972
-12618 -5348 -13974
-12619 -5350 -13973
-12619 -5350 -13973
-12619 -5350 -13972
-12620 -5350 -13973
Similar work flows exist for analog_output, digital_input,
and digital_output. The high-level API also supports many counter
functions too, including count_edges and generate_pulses. For a
full list of convenience functions use the names function in Julia Base:
julia> names(NIDAQ)
25-element Array{Symbol,1}:
:analog_output_channels
:digital_input_channels
:setproperty!
:line_to_line
:counter_input_channels
:counter_output_channels
:NIDAQ
:analog_input_ranges
:digital_input
:stop
:generate_pulses
:count_edges
:digital_output_channels
:analog_input
:channel_type
:analog_output_ranges
:devices
:digital_output
:getproperties
:quadrature_input
:analog_input_channels
:analog_output
:Bool32
:clear
NIDAQmx is a powerful interface, and while NIDAQ.jl provides wrappers
for all of it's functions, it only abstracts a few of them. If these
don't suit your needs you'll have to dive deep into src/functions_V*.jl
and src/constants_V*.jl. Complete documentation of this low-level API
is here and
here.
One situation where the low-level API is needed is to specify continous output of pulses using a counter:
julia> t = generate_pulses("Dev1/ctr0")
NIDAQ.COTask(Ptr{Nothing} @0x00000000059d8790)
julia> fieldnames(typeof(t))
(:th,)
julia> NIDAQ.CfgImplicitTiming(t.th, NIDAQ.Val_ContSamps, UInt64(1))
0
Note that tasks consist of just a single field th, and that this "task
handle" is what must be passed into many low-level routines.
Also, for brevity NIDAQ.jl strips the "DAQmx" prefix to all functions and constants in NI-DAQmx, and converts the latter to 32 bits. One must still take care to caste the other inputs appropriately though.
Install Clang.jl. If there are
build problems, make sure that llvm-config is on your PATH, and that
libclang can be found, as described in the Clang.jl README. Clang
defaults to using a system installed version of LLVM. An alternative is
to set BUILD_LLVM_CLANG=1 in Make.user, and compile Julia from source.
Find NIDAQmx.h, which usually lives in
C:\Program Files (x86)\National Instruments\NI-DAQ\DAQmx ANSI C Dev\include.
Then,
julia> using Clang
julia> context = wrap_c.init()
julia> context.common_file = "common.jl"
julia> context.headers = ["NIDAQmx.h"]
julia> run(context)
$ mv NIDAQmx.h src/NIDAQmx_V<version>.h
$ mv NIDAQmx.jl src/functions_V<version>.jl
$ mv common.jl src/constants_V<version>.jl
The following manual edits are then necessary:
- For NI-DAQmx v9.6.0 in
NIDAQmx.hchangedefined(__linux__)todefined(__linux__) || defined(__APPLE__). - In
constants_V<version>.jl- comment out
const CVICALLBACK = CVICDECL, - in NI-DAQmx v17.1.0 comment out
const CVIAbsoluteTime = VOID - change
const bool32 = uInt32toconst bool32 = Bool32. - in NI-DAQmx v15.1.1 and greater comment out
using Compat
- comment out
- In
functions_V<version>.jl- globally search for
Ptrand replace withRef, then globally search forCallbackRefand replace withCallbackPtr. - globally search for
Cstringand replace withSafeCstring - (for Julia 0.7 support) replace
typewith_type
- globally search for
Ben Arthur, [email protected]
Scientific Computing
Janelia Research Campus
Howard Hughes Medical Institute
