How Can I syncronize between two NI USB-4431 devices?

Question

Hayeong Oh 2020-2-10

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/504598-how-can-i-syncronize-between-two-ni-usb-4431-devices

I tried "demo_synchronize_PCI_using_RTSI.m" in the daq example files in the Data Acquisition Toolbox.

% % Add a start trigger connection to the session using
% % |addTriggerConnection|. In this example, set the source as |'RTSI0/PFI3'|
% % and the destination as |'RTSI0/Dev4'|.
 addTriggerConnection(s,'Dev1/RTSI0','Dev2/RTSI0','StartTrigger');
% 
% %% Add Scan Clock Connections to Session 
% %
% % Similarly use the |RTSI1| terminal connection between the two
% % devices to share the scan clock. Add scan clock connection to the session
% % using |addClockConnection|.
 addClockConnection(s,'Dev3/RTSI1','Dev4/RTSI1','ScanClock');  

But, I found out that NI USB-4431 doesn't support RTSI(?) option.

But when I look up the

s=daq.createSession('ni')

variables, I found out that there's an option with "AutoSyncDSA", whose default value is "0".

So, I tried using below after addAnalogInputChannel.

s.AutoSyncDSA=1

But there's an error as below.

"" Add channels from NI's Dynamic Signal Analyzers devices before setting the AutoSyncDSA property. ""

What is that meaning? I already added channels, but there's still an error like that.

Below is edited version of "demo_synchronize_PCI_using_RTSI.m"..

%% Synchronize NI PCI devices using RTSI
%
% This example shows how to acquire synchronized data from two PCI devices.
% A sine wave is connected to Channel 0 of National
% Instruments(R) PCI-6251 and to Channel 0 of NI PCIe-6363. Both the
% channels are given the same sine wave to verify synchronization.
% Perfectly synchronized channels would show zero phase lag between the two
% acquired signals.
% Copyright 2011-2014 The MathWorks, Inc.
%% Create Session and Add Analog Input Channel
%
% Create a session, and add analog input channels with the |Voltage|
% measurement type, using National Instruments(R) PCI-6251 and 
% NI PCIe-6363.
s = daq.createSession('ni');
addAnalogInputChannel(s,'Dev1', 2, 'Accelerometer');
addAnalogInputChannel(s,'Dev2', 2, 'Accelerometer');
%% Acquire Data without any Synchronization Configuration
%
% Use the |startForeground| command to start the acquisition.  
s.Channels(1,1).Sensitivity=0.1;%volt/g
s.Channels(1,2).Sensitivity=0.1;%volt/g
s.AutoSyncDSA=1;
[data,time] = s.startForeground();
plot(time, data)
%%
% There is a small phase lag between the two channel inputs. The session
% starts the two channels close together, but the devices are not sharing
% any clock and trigger information and therefore will not be perfectly
% synchronized. In this case the acquisitions are near-simultaneous
% acquisition. To synchronize them perfectly  share clock and trigger
% information.
%% Setup Hardware Connections
%
% Connect PCI devices using a RTSI(R) (Real-Time System Integration) cable
% and register it in Measurement & Automation Explorer(R). To synchronize
% acquisition share a scan clock and start trigger between the two devices.
%% 
% *Choosing Source and Destination Devices*
%
% The device that provides the control and timing signals is called the
% source device, and the device that receives these signals is called
% destination device. In this example, we choose |Dev3| as the Source device
% and |Dev4| as the Destination device.
%% Add Start Trigger Connections to Session 
%
% The RTSI cable creates a physical connection between the |RTSI0| terminal
% on |Dev3| and |RTSI0| terminal on |Dev4|. Use this connection to share
% the start trigger between these devices.
%%
% % Add a start trigger connection to the session using
% % |addTriggerConnection|. In this example, set the source as |'RTSI0/PFI3'|
% % and the destination as |'RTSI0/Dev4'|.
%  addTriggerConnection(s,'Dev1/RTSI0','Dev2/RTSI0','StartTrigger');
% 
% %% Add Scan Clock Connections to Session 
% %
% % Similarly use the |RTSI1| terminal connection between the two
% % devices to share the scan clock. Add scan clock connection to the session
% % using |addClockConnection|.
%  addClockConnection(s,'Dev3/RTSI1','Dev4/RTSI1','ScanClock');   
%%
% For a quick summary of the connections type
s.Connections
%% Acquire Data with Synchronization
% Use |startForeground| to start the acquisition.  
[data,time] = s.startForeground();
plot(time, data)
%%
% The two sine waves are overlapping with zero phase lag confirming that
% your devices are completely synchronized.