tab: Sercos Module – Oversampling

Object: Sercos Module

In this slave tab, you can use the oversampling function for reading of special input channels faster than permitted by the bus cycle time. For example, you can read analog entries in 125µs although the cycle time of the bus is only 1ms.

There are 8 data channels available in the I/O mapping with this setting. In addition, the signals are transmitted to the normal signals. In this way, you can use the normal input and the oversampled signals at the same time.

The Oversampling tab is shown only when the module supports this function.

Tip

If the connection type of the slave is not set to clock synchronous, then a confirmation prompt opens when activating the oversampling. In this dialog. the connection type is adjusted automatically.

Table 9. Oversampling Configuration

Oversampling domain	The list of possible signals is defined in the device description. It displays the available oversampling units of the device.
Number of samples	Sampling within a bus cycle. Depends on each module and the Sercos cycle time. There are modules that permit only certain fixed ratios (for example, 1,2,4,8). In addition, the module prescribes a minimum sampling rate that cannot be undershot. For example, if the minimum time is 7.81µs, then a maximum number of 128 is possible for a cycle time of 1ms (1ms / 128 = 7.8125µs).
Sampling time (µs)	Used for display only. Computed from the Sercos cycle time and the Number of samples. The single values are recorded in this time frame.
Control/Status	: The control and status word is also transmitted. The respective I/O channels are added in the Sercos Module I/O Mapping dialog.
Required Sercos cycle time	Shows the minimum Sercos cycle time that is required for not undershooting the smallest sampling interval. For example, if the device has a minimum sampling rate of 7.81µs and the number of samples is set to 16, then the Sercos cycle time has to be at least 125µs.
Symbolic values	: Shows the designations of the I/O channels that are mapped to the signals of the oversampling domains. : The signals are displayed as IDN/offset/length.
Channel IDN / Offset / Length	Signals of the selected OVS domains. : Oversampling is activated for the selected channel. The number of I/O channels that are added depends on the set number of samples. The original, normal signal remains and it is identified as "oversampled" in the channel name. Note: As soon as the channels are activated, the other unactivated channels can be blocked if the module supports only a limited number of signals. Then the message is shown: "Only n signals can be oversampled at the same time."
Select All	All signals are activated or deactivated.
Select None