Acquire Data from Multiple Channels

This example uses:

This example shows how to acquire data from multiple channels, and from multiple devices on the same chassis. In this example, you acquire voltage data from an NI 9201 device with ID cDAQ1Mod4 and an NI 9205 device with ID cDAQ1Mod1.

Create DataAcquisition Object and Add Channels from Two Devices

Create a DataAcquisition object. Add two analog input voltage channels for cDAQ1Mod1 with channel IDs 0 and 1 using the addinput function.

d = daq("ni");
addinput(d,"cDAQ1Mod1",0:1,"Voltage")
ch = 

    Index   Type      Device      Channel   Measurement Type         Range              Name   
    _____   ____    ___________   _______   ________________   __________________   _______________

      1     "ai"    "cDAQ1Mod1"   "ai0"     "Voltage (Diff)"   "-10 to +10 Volts"   "cDAQ1Mod1_ai0"
      2     "ai"    "cDAQ1Mod1"   "ai1"     "Voltage (Diff)"   "-10 to +10 Volts"   "cDAQ1Mod1_ai1"

Add an additional channel for a separate device, cDAQ1Mod6 with channel ID 0. For NI devices, use either a terminal name, like ai0, or a numeric equivalent like 0. Then view all channels on the DataAcquisition object.

ch = addinput(d,"cDAQ1Mod6","ai0","Voltage");
d.Channels
    Index   Type      Device      Channel   Measurement Type         Range              Name   
    _____   ____    ___________   _______   ________________   __________________   _______________

      1     "ai"    "cDAQ1Mod1"   "ai0"     "Voltage (Diff)"   "-10 to +10 Volts"   "cDAQ1Mod1_ai0"
      2     "ai"    "cDAQ1Mod1"   "ai1"     "Voltage (Diff)"   "-10 to +10 Volts"   "cDAQ1Mod1_ai1"
      3     "ai"    "cDAQ1Mod6"   "ai0"     "Voltage (Diff)"   "-10 to +10 Volts"   "cDAQ1Mod6_ai0"

Acquire and Plot Data from All Channels

Acquire data for a duration of one second using the DataAcquisition object d, store it in the variable data as a matrix, and plot the acquired data.

data = read(d,seconds(1),OutputFormat="Matrix");
plot(data)
title('Acquired Data from Multiple Channels');
xlabel('Sample Number');
ylabel('Voltage (V)');
legend('ai0 -cDAQ6Mod1','ai1 -cDAQ6Mod1','ai0 -cDAQ6Mod3');

plot acquired data from multiple channels

Configure Second Device Channel

Edit and display the properties of the channel ai0 on cDAQ1Mod6. For more information, see Channel Properties.

ch.TerminalConfig ="SingleEnded";
ch.Name = "Velocity_sensor";
ch
ch = 

 Index   Type     Device      Channel     Measurement Type           Range               Name   
 _____   ____   ___________   _______   ____________________   __________________  _________________

   1     "ai"   "cDAQ1Mod6"   "ai0"     "Voltage (SingleEnd)"  "-10 to +10 Volts"  "Velocity_sensor"

Acquire Data from All Channels

Acquire data for a duration of one second and store it in the variable data as a matrix.

data = read(d,seconds(1),OutputFormat="Matrix");

Plot Data from Each Device Separately

Plot acquired data in two subplots: the first plot shows voltage signals from Device 1, and the second plot shows the signal from Device 2. 

figure;
subplot(2,1,1);
plot(data.Time,[data.cDAQ6Mod1_ai0 data.cDAQ6Mod1_ai1]);
title('Acquired Data from Device 1');
xlabel('Time (s)');
ylabel('Voltage (V)');
subplot(2,1,2);
plot(data.Time,data.Velocity_sensor);
title('Acquired Data from Device 2');
xlabel('Time (s)');
ylabel('Voltage (V)');

plot acquired data from multiple devices

See Also

Functions

Topics