PXIe-6739 and PXIe-4138 integration using MATLAB

[Levent_EE]

Hi,
My goal is supplying a DC voltage (using PXIe-4138) to my setup and measure the current (drained from the source) vs time while I am sending analog control bits (using PXIe-6739) to an analog mux in my hardware. 

I am using MATLAB 2017b (Data Acquisition Toolbox) and ok with sending desired outputs using PXIe-6739. However, I couldn't find a resource for controlling PXIe-4138 while sending data with PXIe-6739.

using MATLAB. When I use daq.getDevices, I don't see PXIe-4138 ( I guess this is expected since it's not a DAQ). 

Looking for suggestions and code examples for controlling 4138 and 6739 together. 

My hardware: PXIe-1078 chasis with  two PXIe-6738s, PXIe-6739 and PXIe-4138. 

Thanks a lot,

Levent

[Tepig]

I don't think there is the specific example. Combining following example is good way.

Acquire Data Using NI Devices

Source DC voltage through NI-DCPOWER MATLAB Instrument Driver in Simulation Mode

Do you have a concern about Synchronization? See this article.

http://zone.ni.com/reference/en-XX/help/370736R-01/ni_dc_power_supplies_help/mi_synchronization/

[Levent_EE]

Hi Emboar, 

I am using these two examples but have two questions.

Acquire Data Using NI Devices

Source DC voltage through NI-DCPOWER MATLAB Instrument Driver in Simulation Mode

1- Measure current for few seconds requires multiple current measurements. 

measurementType = 0; (instead of =1) makes it a current measurement, but it measures single data point. I would like to take many measurements during this time period, so I need to change measure_record_length somehow. 

measure = get(ictObj, 'measure'); % this measure object has Measure_Record_Length but I couldn't change it 😞

I guess invoke(measure,'???', desired_length) should solve the problem but couldn't find the list of commands to change this parameter. 

2- I need synchronization and planning to use signal based sync. Are there any MATLAB example codes ? All the links are for LabView.  I am guessing it will just take few lines of code in Matlab. 

Thanks a lot !!! 

Levent

[Machop]

1. What are the results you are getting?

2.There are some informaitona bout syncronization on MATLAB

https://www.mathworks.com/help/daq/multiple-device-synchronization.html

[Levent_EE]

---

@Machop wrote:

1. What are the results you are getting?

2.There are some informaitona bout syncronization on MATLAB

https://www.mathworks.com/help/daq/multiple-device-synchronization.html

---

1- I couldn't get a continuous measurement yet. I set the source mode to sequence but it doesn't work and couldn't find an example code.
Any help appreciated. 

The error message that I am getting: 

"The instrument returned an error while executing the function.
A sequence must have at least one step." 

%
close all
clc
clear

% driversInfo = instrhwinfo ('ivi');
% disp(driversInfo.Modules');
%
ictObj = icdevice('nidcpower.mdd', 'DAQ::PXI1Slot5');
% disp(ictObj);
channel = '0';
src=get(ictObj, 'source');

% Configure the Source mode to Sequence ( 1020 for Single Point)
sourceMode = 1021;
invoke(src, 'configuresourcemode', sourceMode);

% Set the output function to DC Voltage
outputFunction = 1006;
invoke(src, 'configureoutputfunction', channel, outputFunction);

srcDCVoltage = get(ictObj, 'sourcedcvoltage');

% Configure the Voltage level, in volts, for the output channel generation
voltageLevel = 1.2;
invoke(srcDCVoltage, 'configurevoltagelevel', channel, voltageLevel);

% Initiate the device to start generation
control = get(ictObj, 'control');

measure = get(ictObj, 'measure');
% invoke(measure, 'configuremeasurerecordlength', channel, 82);
invoke(control, 'initiate');
% Measure current
measurementType = 0;
amps = invoke(measure, 'measure', channel, measurementType);

[Machop]

Can you share exactly what you are doing, and what errors, or messages are you receving? With this I can check if I can duplicate the behaviour.