bernard ang

Automate with DAQ switching modules

Blog Post created by bernard ang Employee on Aug 1, 2017

Data acquisition (DAQ) instruments can normally meet many application needs by its scanning mode and universal input capabilities. With its scanning mode, you can configure each of its channels to measure various types of inputs such as AC/DC Volts, AC/DC Current, Resistances, signal frequency and temperatures. With its built in DMM, you can do a lot of measurements. However,

·        What if you want to use the DAQ for switching purpose?

·        What if you have measurements that consists of a matrix of different tests and multiple DUTs?

·        What if you want to perform data logging on measurements that cannot be done by the DAQ’s built in DMM i.e. high frequency power and other measurements?

·        What if you want to provide multiple sources or loads into your DUT(s) i.e. AC or DC source, arbitrary waveform, electronic loads, etc?

Suddenly, switch modules become really handy. Please refer to the module selection guide below.

Module selection guide

34901A, 34902A and 34908A can be used as scanning modules and also as switching modules. Differences are its relay switches with tradeoffs between switching speed and power handling.

34903A has dedicated SPDT switching relays that can drive actuators as well as general switching applications.

34904A is a dedicated 4 X 8 switch matrix.

34905A and 34906A are RF switch multiplexers with 50 and 75 termination respectively.

So, how do you AUTOMATE with your DAQ switching modules?

·        Simple automation without programming would be to use the BenchVue DAQ software. Figure below shows graphical switches you can easily toggle the switches

BenchVue graphical switches

·        Figure below shows a simple Testflow graphical tool toggling a switch 10 times

Testflow switching

In the command expert, this SCPI command to switch open channel 101 is as shown below:

Command expert

:ROUTe:OPEN (@101)

Similarly, to close switch channel 101, it is

:ROUTe:CLOSE (@101).

To speed up your automation, you can switch on/off a group of switches in a single command. Here are two examples:

-         Switch open channels 01 through 05 on the module in slot 100. ROUTe:OPEN (@101:105)

-         Close Switch channels 02 through 07 and 09 on the module in slot 200 and channels 02 through 08 on the module in slot 300


For more information on Keysight’s general purpose DAQ instruments, please visit:

For more information on Keysight’s BenchVue software, please visit: