# Select Previous Identifier Number - 10117

It is possible to use the signal Select Previous Identifier Number when a task in the virtual station is configured as:

- Batch Sequence

- Source Tightening

- Source Batch

  - Number Identifier method

  - String Identifier method

ST Selector configurable functions Take Next and Take Previous enable the input signals Select Next Identifier Number and Select Previous Identifier Number.

## Batch Sequence selected as Virtual Station Task

If Free Order switch has been enabled, the signal Select Previous Identifier Number can select different batches within the selected sequence.

Before selecting batches, it is mandatory that they have the identifier number assigned. If a batch does not have the identifier number assigned, the signal Select Previous Identifier Number cannot select it, even if Free Order switch is enabled.

It enables looping through the batches that have a configured identifier number.
If identifier number is "None", it is possible to select it only after all Batches with configured identifier number are completed.

It is possible to do looping, but 0 is skipped. When a batch is finished, it is no longer selectable.

For example, in case of batches with assigned identifier numbers 1,2,4,5, the signal runs in loop: 5,4,2,1,5,4,2... as long as the batches are not finished.

## Source Tightening selected as Virtual Station Task

The signal selects the previous identifier number from the list of tightening programs specified in the Source Tightening task.
The selection runs from the currently selected identifier number to the previous lower one.

When the smallest identifier number is selected, this signal selects 0; after 0, the signal selects the next smaller identifier number.

If 0 is selected as identifier number, the tool is locked.

If the tightening program is assigned to an identifier number and then it is removed from the list of tightening programs, it is still possible to select this identifier number. In this case, the tool is locked because there is not a specific tightening program.

When Selector Mode switch is set to Confirm, the socket selector needs to be assigned and configured. All tightening programs can be selected, but before running them, appropriate socket must be lifted from the socket selector.

## Source Batch selected as Virtual Station Task

In Sources > Batch Sequence > Source Batch, when the identifier method is set to Number, the signal Select Previous Identifier Number selects sequences from a list of sequences shown in Source Batch task.

It is possible to do looping through 0. The signal Select Previous Identifier Number selects only the identifier numbers assigned to sequences.

For example, if there are 4 sequences available with identifier numbers 1,2,4, and 8, the signal Select Previous Identifier Number iterates and selects 8,4,2,1,0,8,4...

The identifier numbers not defined are not selected.

In Sources > Batch Sequence > Source Batch, when the identifier method is set to String, it is necessary to select the sequence through external sources (like scanner or Open Protocol). The signal Select Previous Identifier Number is able to select the batches within the selected sequence.

Name in SoftPLC: SELECT_PREVIOUS_ID_NUMBER

Signal Type | Value Type | Size Min [bit] | Size Max [bit]
--- | --- | --- | ---
Event | Boolean | 1 | 1

## Devices

- Fieldbus: TRUE

- Indicator Box: FALSE

- Internal I/O: TRUE

- Operator Panel: TRUE

- Tool Functions: TRUE

- ST Selector: TRUE

- Stacklight: TRUE

- TLS Tag: FALSE

- I/O Expander: TRUE