# Editing Start and End Instances

It is possible to edit start and end instances for the fieldbus mapping.

The start and end instances are the fixed positions that defines where the acyclic fieldbus configuration should start and end. It is important to enter the correct range.

1. Select the Acyclic from controller tab in the Virtual Station Mapping Configuration field.

2. Edit the Start instance and End instance values if required.

   If the correct value is not entered, a warning "The fieldbus frame must fit its content" is displayed.

## Lowest/First Possible Acyclic Data Instance Numbers

Fieldbus | To Controller Instance Number | From Controller Instance Number
--- | --- | ---
Profinet-IO | 32767 | 2048
Profibus-DP | 65025 | 2048
Ethernet/IP | 65535 | 2048
DeviceNet | 65535 | 2048
CC-Link | Not supported | Not supported
CC-Link IE | 65535 | 2048

- After each tightening, the measured values for the configured items are available as acyclic data for the PLC to read from the system. The data is updated with new values after each tightening.

- When the signal Cycle Complete is set to high, the data is ready to be read. The data is valid until the next tightening starts, that is until the input signal Start is sent.

- The PLC issues a series of GET_RECORD commands to collect all the data.