Oversampling terminals/box modules and TwinCAT Scope

Generally, input data of a terminal/box could be achieved by the scope either directly (via the activated ADS server) or by creation of a PLC variable which is linked to the PDO of a terminal/box for recording them. Both procedures will be explained for TwinCAT 3 (TC3) at first and for TwinCAT 2 (TC2) respectively.

Oversampling means that an analog or digital input device supplies not only one measured value for each process data cycle/EtherCAT cycle (duration T), but several, which are determined at a constant interval t < T. The ratio T/t is the oversampling factor n.

A channel thus offers not only one PDO for linking in the process data, as in the example here with the EL3102, but n PDOs as in the case of the EL3702 and other oversampling terminals/box modules.

The definition of “oversampling” by the Beckhoff’s point of view shouldn’t be mixed up with the oversampling process of a deltaSigma ADC:

For example, these both procedures are arranged sequentially by their technical implementation within the EL3751 and can also be present simultaneously.

Oversampling terminals/box modules and TwinCAT Scope 1:
Oversampling PDO of the EL37xx series and in the comparison with EL31xx

Accordingly, the Scope2 (TC2) or ScopeView (TC3) can read in and display several PDOs per cycle in correct time.