Optimization of response times

In the case of SEW‑EURODRIVE inverters, data processing within the inverter is influenced via the Consistent data transfer parameter (parameter group [Device properties] > [Communication] > [Fieldbus] > [AS-Interface slave]).

The parameter is only effective for the following device types:

A/B device
Double device

Since the cyclic data exchange for these device types takes place sequentially over several basic cycles, the parameter can be used to optimize the response time.

Devices with extended address range A or B

Setting	Meaning
Yes (default setting)	The AS-Interface communication option only forwards the cyclic data bits to the process data processing element of the inverter when they have been completely transmitted. The current states of the status bits from the inverter's process data processing element are frozen for the entire transmission period when the transmission to the master begins. Advantage: The data is processed as a consistent data block. Disadvantage: The response time to control commands and status signals corresponds to the transmission time of the respective device profile (maximum 20 ms – 40 ms).
No	The AS-Interface communication option forwards the transmitted data bits to the process data processing element of the inverter after each AS‑Interface basic cycle. The current states of the status bits from the inverter's process data processing element are also transmitted to the master with each of the AS-Interface basic cycles. Advantage: The response time to control commands and status signals only depends on the AS‑Interface basic cycle (maximum 10 ms). Disadvantage: The data block of the control bits and status bits is no longer consistent. Depending on the device profile used, the data bits are transmitted sequentially in packets of 2 bits of payload data. This must be taken into account when configuring and processing the data. For further information about data consistency, refer to chapter AS‑Interface device profile.

Setting

Meaning

Yes
(default setting)

The AS-Interface communication option only forwards the cyclic data bits to the process data processing element of the inverter when they have been completely transmitted.

The current states of the status bits from the inverter's process data processing element are frozen for the entire transmission period when the transmission to the master begins.

Advantage:

The data is processed as a consistent data block.

Disadvantage:

The response time to control commands and status signals corresponds to the transmission time of the respective device profile (maximum 20 ms – 40 ms).

The AS-Interface communication option forwards the transmitted data bits to the process data processing element of the inverter after each AS‑Interface basic cycle. The current states of the status bits from the inverter's process data processing element are also transmitted to the master with each of the AS-Interface basic cycles.

Advantage:

The response time to control commands and status signals only depends on the AS‑Interface basic cycle (maximum 10 ms).

Disadvantage:

The data block of the control bits and status bits is no longer consistent. Depending on the device profile used, the data bits are transmitted sequentially in packets of 2 bits of payload data. This must be taken into account when configuring and processing the data. For further information about data consistency, refer to chapter AS‑Interface device profile.

Binary devices

In the case of the binary device, all 4 cyclic data bits are transmitted within the AS-Interface basic cycle.

The parameter setting does not have an influence on the response times and is ignored.