Difference between revisions of "NI-DAQmx and NI-DAQmx Base examples"
Line 406: | Line 406: | ||
'''Digital inputs/outputs''' | '''Digital inputs/outputs''' | ||
− | Most of DAQ cards have two types of digital ports (input/output): correlated and static. Static ports are software timed, correlated are software and hardware timed by the connection of external clock or internally for example couter output signal ('''/Dev1/Ctr0InternalOutput''' - couter0 as clock ). Check the documention to find it, for example NI-PCI6250 have | + | Most of DAQ cards have two types of digital ports (input/output): correlated and static. Static ports are software timed, correlated are software and hardware timed by the connection of external clock or internally for example couter output signal ('''/Dev1/Ctr0InternalOutput''' - couter0 as clock ). Check the documention to find it, for example NI-PCI6250 have three 8-bit ports: port0 - correlated, port1,port2 - static; NI-PCI6224 two ports: 32-bit port0 - correlated, 8-bit port1 - static. |
To control 8-bit and 32-bit use an appropriate function '''DAQmxReadDigitalU8''', '''DAQmxWriteDigitalU8''' and '''DAQmxReadDigitalU8''', '''DAQmxWriteDigitalU8'''. | To control 8-bit and 32-bit use an appropriate function '''DAQmxReadDigitalU8''', '''DAQmxWriteDigitalU8''' and '''DAQmxReadDigitalU8''', '''DAQmxWriteDigitalU8'''. | ||
+ | |||
+ | ''Different behaviour of collerated port0 occured under Linux and Windows: software timed works only under Windows, with external clock works under Windows and Linux!!!'' | ||
Software timed digital input. To check it, connected +5V(depend on hardware) to one of aviable pins. | Software timed digital input. To check it, connected +5V(depend on hardware) to one of aviable pins. | ||
− | |||
− | |||
[[Category:Hardware]] | [[Category:Hardware]] |
Revision as of 11:55, 18 November 2014
INTRODUCTION
National Instruments produce a wide range of DAQ cards, which generally used for acquiring a generating signals. [1] These cards usually have a few numbers of analog inputs/outputs, digital inputs/ouputs, counters and frequency generator with hardware/software timing. Exiting of feature (type, number, parameters) on card depends on card type.
NIDAQmxBase.pas and NIDAQmx.pas are provided pascal bindings to National Instruments libraries and enabled control NI DAQ cards from program writing on FreePascal.
What National Instruments Hardware are supported
Supported hardware list by NI-DAQmx and NI-DAQ Driver for different operation system [2]
NI-DAQmxBase library
NI-DAQmxBase library or driver is multiplatform library for Linux, Windows and MacOS X, but doesn't implement all device features. For example, digital input/output ports speed is limited by computer speed ~100kHz, because DMA data tranfer is not supported.
Download library for Linux [3], Windows [4], MacOS X [5]. Read readme.txt file to find the list of supported hardware and hardware features.
NI-DAQmx library
Actual (newest) NI-DAQmx library is available only for Windows today.
Download it there [6]
NI-DAQmx version 8.0.2 is also available for Linux 32-bit. You can use it with enterprise RHEL 5,6 distribution or with it clones CentOS 5,6 and Scientific Linux 5,6 or you can use it with old version Linux distribution with kernel 2.6.x.
Download it there [7]
Read readme.txt file to find the list of supported hardware and hardware features.
PASCAL bindings
Your can download pascal bindings nidaqmxbase.pas and nidaqmx.pas in this forum thread [8]
NI-DAQmx examples
Get device list
You can check device list names using NI MAX program under Windows or nilsdev utility under Linux.
program devicelist;
{$mode objfpc}{$H+}
uses
{$IFDEF UNIX}{$IFDEF UseCThreads}
cthreads,
{$ENDIF}{$ENDIF}
Classes,nidaqmx,SysUtils
{ you can add units after this };
var
devicenames:array of Char;
infostr:string;
DeviceNamesList:TStringList;
buffersize:longint;
product_type:array of char;
devserialnum,is_simulated:longint;
is_simulated_str:string;
i:byte;
begin
DeviceNamesList:=TStringList.Create;
try
{**************************************************************************
Get device names present in the system
**************************************************************************}
//get buffer size or length of string of device list
buffersize:=DAQmxGetSystemInfoAttribute(DAQmx_Sys_DevNames,devicenames[0],[0]);
//set array of Char lenght
if Buffersize<>0 then begin
writeln('-------------------------------------------------------------');
writeln('|Device name | Product Type | # Serial number | Is Simulated?');
writeln('-------------------------------------------------------------');
SetLength(devicenames,buffersize);
//get the device list
DAQmxGetSystemInfoAttribute(DAQmx_Sys_DevNames,devicenames[0],[buffersize]);
//convert it to string: names are separated by comma
SetString(infostr,PChar(@devicenames[0]),buffersize);
//add names to TStringList
DeviceNamesList.CommaText:=infostr;
{************************************************************************
Get Product info
***********************************************************************}
for i:=0 to DeviceNamesList.Count-1 do begin
//get buffer size or length of string of product type
buffersize:=DAQmxGetDeviceAttribute(@DeviceNamesList.Strings[i][1],DAQmx_Dev_ProductType,Nil);
//set lenght of array of char
SetLength(product_type,buffersize);
//get product type info
DAQmxGetDeviceAttribute(@DeviceNamesList.Strings[i][1],DAQmx_Dev_ProductType,product_type[0],[buffersize]);
{***********************************************************************
Get Serial Number
**********************************************************************}
DAQmxGetDeviceAttribute(@DeviceNamesList.Strings[i][1],DAQmx_Dev_SerialNum,devserialnum,[1]);
//DeviceInfoGrid.Cells[3,i+1]:=IntToHex(devserialnum,8);
{***********************************************************************
Is simulated?
***********************************************************************}
DAQmxGetDeviceAttribute(@DeviceNamesList.Strings[i][1],DAQmx_Dev_IsSimulated,is_simulated,[1]);
if is_simulated = 0 then is_simulated_str:='No'
else is_simulated_str:='Yes';
//Show info
writeln('| ',DeviceNamesList.Strings[i],' | ',PChar(@product_type[0]),' | $',IntToHex(devserialnum,8),' |',is_simulated_str);
end;
end
else writeln('any device found');
finally
DeviceNamesList.Free;
end;
end.
Output example
-------------------------------------------------------------
|Device name | Product Type | # Serial number | Is Simulated?
-------------------------------------------------------------
| Dev1 | PCI-6250 | $018D0B90 |No
Get channel names
program chaninfo;
{$mode objfpc}{$H+}
uses
{$IFDEF UNIX}{$IFDEF UseCThreads}
cthreads,
{$ENDIF}{$ENDIF}
Classes,nidaqmx
{ you can add units after this };
var
buffersize,infotype:longint;
channelnames:array of char;
MsgChannelNames:array [0..255] of char;
MsgNoChannelsText:array [0..255] of char;
channeltype:byte;
DeviceName:string;
begin
{**********INPUT Device name and interested channel type **********************
**********WITHOUT CHEKING IF DEVICE EXITS IN THE SYSTEM**********************}
write('Enter device name, for example Dev1, Dev2 etc.: ');
readln(Devicename);
writeln('0 - analog inputs');
writeln('1 - analog outputs');
writeln('2 - digital inputs');
writeln('3 - digital outputs');
writeln('4 - counter inputs');
writeln('5 - counter outputs');
write('choose the number of required channel type:');
readln(channeltype);
{**********CHANNEL TYPE CHOSEN**********************************************}
case channeltype of
{********************ANALOG INPUTS NAMES*************************************}
0: begin
infotype:=DAQmx_Dev_AI_PhysicalChans;
MsgChannelNames:='Analog input names';
MsgNoChannelsText:='There are no analog inputs';
end;
{********************ANALOG OUTPUTS NAMES************************************}
1: begin
infotype:=DAQmx_Dev_AO_PhysicalChans;
MsgChannelNames:='Analog output names';
MsgNoChannelsText:='There are no analog outputs';
end;
{********************DIGITAL INPUT PORTS NAMES*******************************}
2: begin
infotype:=DAQmx_Dev_DI_Ports;
MsgChannelNames:='Digital input ports';
MsgNoChannelsText:='There are no digital input ports';
end;
{********************DIGITAL OUTPUT PORTS NAMES******************************}
3:begin
infotype:=DAQmx_Dev_DO_Ports;
MsgChannelNames:='Digital output ports';
MsgNoChannelsText:='There are no digital output ports';
end;
{********************COUNTER INPUT NAMES******************************}
4:begin
infotype:= DAQmx_Dev_CI_PhysicalChans;
MsgChannelNames:='Digital counter inputs';
MsgNoChannelsText:='There are no counter inputs ';
end;
{********************COUNTER OUTPUT NAMES******************************}
5:begin
infotype:= DAQmx_Dev_CO_PhysicalChans;
MsgChannelNames:='Digital counter outputs';
MsgNoChannelsText:='There are no counter outputs ';
end;
end;
{************GET CHANNEL NAMES*********************************************}
if (channeltype>=0) and (channeltype<6) then begin
//get buffer size or length of channelnames
buffersize:=DAQmxGetDeviceAttribute(@DeviceName[1],infotype,Nil);
if buffersize<>0 then begin
SetLength(channelnames,buffersize);
//get analog channel names separated by comma
DAQmxGetDeviceAttribute(@DeviceName[1],infotype,channelnames[0],[buffersize]);
//show info
writeln(MsgChannelNames+': '+PChar(@channelnames[0]));
end
else writeln(MsgNoChannelsText);
end;
end.
Output example
Enter device name, for example Dev1, Dev2 etc.: Dev1
0 - analog inputs
1 - analog outputs
2 - digital inputs
3 - digital outputs
4 - counter inputs
5 - counter outputs
choose the number of required channel type:0
Analog input names: Dev1/ai0, Dev1/ai1, Dev1/ai2, Dev1/ai3, Dev1/ai4, Dev1/ai5, Dev1/ai6, Dev1/ai7, Dev1/ai8, Dev1/ai9, Dev1/ai10, Dev1/ai11, Dev1/ai12, Dev1/ai13, Dev1/ai14, Dev1/ai15
Acquire finite samples from one analog input
program aichan;
{$mode objfpc}{$H+}
uses
{$IFDEF UNIX}{$IFDEF UseCThreads}
cthreads,
{$ENDIF}{$ENDIF}
Classes, nidaqmx
{ you can add units after this };
var
AITaskHandle:TaskHandle;
data:array[1..1000] of double;
reads,i:longint;
{************Error handling procedure *****************************************
Example:
ErrorCheck(DAQmxCreateAIVoltageChan(AITaskHandle,'Dev1/ai0','',DAQmx_Val_RSE,-10.0,10.0,DAQmx_Val_Volts,NIL),AITaskHandle);
*******************************************************************************}
procedure ErrorCheck(AError:longint;ATaskHandle:longint);
var
errBuffer:array[0..2048] of char;
begin
//get error description
if Aerror<>0 then begin
DAQmxGetExtendedErrorInfo(@ErrBuffer[0],2048);
writeln(PChar(@ErrBuffer[0]));
//stop and cleat task
if Assigned(@ATaskHandle) then begin
DAQmxStopTask(ATaskHandle);
DAQmxClearTask(ATaskHandle);
end;
//stop program
Halt;
end;
end;
{*********************MAIN PROGRAM*********************************************
******************* without error handling************************************}
begin
//create task
DAQmxCreateTask('',@AITaskHandle);
//create analog input channel Dev1/ai0 (activate it)
//voltage range -10 - 10
DAQmxCreateAIVoltageChan(AITaskHandle,'Dev1/ai0','',DAQmx_Val_RSE,-10.0,10.0,DAQmx_Val_Volts,NIL);
//set timing
//Sample rate = 10000 (10 kHz), sample per channel =1000
//acquire finite samples (1000 samples) defined by DAQmx_Val_FiniteSamps
DAQmxCfgSampClkTiming(AITaskHandle,'OnboardClock',10000.0,DAQmx_Val_Rising,DAQmx_Val_FiniteSamps,1000);
//start task
DAQmxStartTask(AITaskHandle);
//acquire 1000 samples
DAQmxReadAnalogF64(AITaskHandle,1000,10.0,DAQmx_Val_GroupByChannel,@data[1],1000,@reads,NIL);
//show first 10 samples
writeln(reads,' samples were acquired');
writeln('');
writeln('Value of first 10 samples');
for i:=1 to 10 do writeln('sample[',i,'] = ',data[i]:4:2,' V');
//stop and clear task
DAQmxStopTask(AITaskHandle);
DAQmxClearTask(AITaskHandle);
end.
Output example
1000 samples were acquired
Value of first 10 samples
sample[1] = 0.23 V
sample[2] = 0.23 V
sample[3] = 0.23 V
sample[4] = 0.23 V
sample[5] = 0.23 V
sample[6] = 0.23 V
sample[7] = 0.23 V
sample[8] = 0.23 V
sample[9] = 0.23 V
sample[10] = 0.23 V
Continually acquire samples from 3 analog channels
program multiaichannel;
{$mode objfpc}{$H+}
uses
{$IFDEF UNIX}{$IFDEF UseCThreads}
cthreads,
{$ENDIF}{$ENDIF}
Classes, nidaqmx,crt
{ you can add units after this };
var
AITaskHandle:TaskHandle;
data:array of double;
reads:longint;
totalsamplereads:longint=0;
i:longint;
{************Error handling procedure *****************************************
Example:
ErrorCheck(DAQmxCreateAIVoltageChan(AITaskHandle,'Dev1/ai0','',DAQmx_Val_RSE,-10.0,10.0,DAQmx_Val_Volts,NIL),AITaskHandle);
*******************************************************************************}
procedure ErrorCheck(AError:longint;ATaskHandle:longint);
var
errBuffer:array[0..2048] of char;
begin
//get error description
if Aerror<>0 then begin
DAQmxGetExtendedErrorInfo(@ErrBuffer[0],2048);
writeln(PChar(@ErrBuffer[0]));
//stop and cleat task
if Assigned(@ATaskHandle) then begin
DAQmxStopTask(ATaskHandle);
DAQmxClearTask(ATaskHandle);
end;
//stop program
Halt;
end;
end;
{*********************MAIN PROGRAM*********************************************
******************* without error handling************************************}
begin
//Set buffer size for data acquiring, sample per channel 1000
//buffer size(data -array variable) = 3 channel * 1000 samples per channel
Setlength(data,3*1000);
//create task
DAQmxCreateTask('',@AITaskHandle);
//create analog input channel Dev1/ai0:2 (activate 3 channels)
//voltage range -10 - 10
DAQmxCreateAIVoltageChan(AITaskHandle,'Dev1/ai0:2','',DAQmx_Val_RSE,-10.0,10.0,DAQmx_Val_Volts,NIL);
//set timing
//Sample rate = 10000 (10 kHz), sample per channel =1000
//acquire finite samples (1000 samples) defined by DAQmx_Val_Cont_Samps
DAQmxCfgSampClkTiming(AITaskHandle,'OnboardClock',10000.0,DAQmx_Val_Rising,DAQmx_Val_ContSamps,1000);
//start task
DAQmxStartTask(AITaskHandle);
//acquire 10000 samples for each channel
while totalsamplereads<10000 do begin
//1000- sample rate, 3000 - buffer size(data -array variable) = 3 channel * 1000 samples per channel
DAQmxReadAnalogF64(AITaskHandle,1000,10.0,DAQmx_Val_GroupByChannel,@data[0],3000,@reads,NIL);
totalsamplereads:=totalsamplereads+reads;
writeln('aquired number of samples: ',totalsamplereads);
end;
//show first 10 samples from last 1000 samples acquired from each channel
writeln('');
writeln('Value of first 10 samples of last 1000 samples for each channel');
writeln('| chan0 | chan1 | chan2 | ');
for i:= 0 to 9 do writeln('|',data[i]:5:2,' V| ',data[i+1000]:5:2,' V| ',data[i+2000]:5:2,' V|');
//stop and clear task
DAQmxStopTask(AITaskHandle);
DAQmxClearTask(AITaskHandle);
end.
Output example
aquired number of samples: 1000
aquired number of samples: 2000
aquired number of samples: 3000
aquired number of samples: 4000
aquired number of samples: 5000
aquired number of samples: 6000
aquired number of samples: 7000
aquired number of samples: 8000
aquired number of samples: 9000
aquired number of samples: 10000
Value of first 10 samples of last 1000 samples for each channel
| chan0 | chan1 | chan2 |
| 5.07 V| 5.07 V| 5.06 V|
| 5.07 V| 5.07 V| 5.06 V|
| 5.07 V| 5.06 V| 5.07 V|
| 5.06 V| 5.06 V| 5.07 V|
| 5.06 V| 5.07 V| 5.07 V|
| 5.07 V| 5.07 V| 5.06 V|
| 5.07 V| 5.07 V| 5.07 V|
| 5.06 V| 5.06 V| 5.07 V|
| 5.06 V| 5.06 V| 5.06 V|
| 5.07 V| 5.07 V| 5.06 V|
Digital inputs/outputs
Most of DAQ cards have two types of digital ports (input/output): correlated and static. Static ports are software timed, correlated are software and hardware timed by the connection of external clock or internally for example couter output signal (/Dev1/Ctr0InternalOutput - couter0 as clock ). Check the documention to find it, for example NI-PCI6250 have three 8-bit ports: port0 - correlated, port1,port2 - static; NI-PCI6224 two ports: 32-bit port0 - correlated, 8-bit port1 - static.
To control 8-bit and 32-bit use an appropriate function DAQmxReadDigitalU8, DAQmxWriteDigitalU8 and DAQmxReadDigitalU8, DAQmxWriteDigitalU8.
Different behaviour of collerated port0 occured under Linux and Windows: software timed works only under Windows, with external clock works under Windows and Linux!!!
Software timed digital input. To check it, connected +5V(depend on hardware) to one of aviable pins.