Depending on what you are measuring, and mathematics, the channels can have 3 different ways of sampling:

1. Synchronous - These channels have a constant sample rate. If the sample rate is set to 100Hz, there will be a new sample every 1ms. (Analog in channels from Sirius, DEWE-43,..)

2. Asynchronous - The sample rate of these channels is not constant (CAN channels)

3. Single value - There is only one value through the whole measurment (this can be created with a single value option in basic statistics). There are also some other mathematics which output such a result for example sound level.  

There are different options to check the sampling of the channel. Here are some of the options:

In the channel setup:

With more button add the Channels module. In the setup of each channel it is possible to find the sampling type.

During measurement:

Right click on the channel and go to properties. The sampling type can be found in the information tab.