The system determines license demand for Foundation Fieldbus devices based on modules being configured with fieldbus extended blocks. An extended function block is a block that you create in a module and assign to a fieldbus device. The resulting extended block resides in the controller and communicates with the function block running in a fieldbus device.
The table shows the number of signal-bearing parameters for certain extended blocks when configured in modules.
| Extended block name | DI | AI | DO | AO |
|---|---|---|---|---|
| FFAI | 1 | |||
| FFAI_RMT | 1 | |||
| FFAO | 1 | |||
| FFAO_RMT | 1 | |||
| FFDI | 1 | |||
| FFDO | 1 | |||
| FFMAI | 8 | |||
| FFMAI_RMT | 8 | |||
| FFMAO | 8 | |||
| FFMDI | 8 | |||
| FFMDI_STD | 8 | |||
| FFMDO | 8 | |||
| FFMDO_STD | 8 |
All signal-bearing parameters in these extended blocks are available to the module and can contribute to the I/O license demand, even if there are no module references to the signal-bearing parameters configured.
The system requires only one I/O license for references to as many as 16 I/O signal-bearing parameters per device. The system consumes a single license of the most expensive type used. The license costs are (from highest to lowest): AO, AI, DO and DI. For Foundation Fieldbus devices with more than 16 signal parameters referenced by modules, the 15 least expensive I/O parameters do not require a license. The remaining parameters each cause an I/O license demand.
For example, creating an extended block in a module for an FFAI function block in a device costs one AI license regardless of the parameters in the function block that are referenced by this or other modules. (OUT, OUT_D, and FIELD_VAL can all be referenced, but the I/O license demand can never be more than one AI.)
The figure shows the I/O parameters used and the resulting license requirements. Each extended block used has 8 I/O signal-bearing parameters. This results in 24 license-related items. One I/O license is required for 16 of the items. The remaining 8 items each require a license. This results in a total license demand of 9 AI.
