Description
In STEP 7 V10.5, you can only call as multi-instance the function blocks from the libraries supplied with STEP 7 Basic. For example, in the standard blocks for times and counters and for the communication blocks "TSEND_C" and "TRCV_C". You cannot call as multi-instances function blocks that you have created yourself. This functionality will only be available in a future version of STEP 7 Basic.

Fig. 01 shows an example of how the two communication blocks "TSEND_C" and "TRCV_C" are called as multi-instances in FB10. The two standard function blocks called deposit their data in the instance data block DB10 of the calling block FB10. In the declaration of FB10, the multi-instance block calls are stored as static variables.

Fig. 01

If you call a function block as multi-instance from the library, the standard function block called stores its data in the instance data block of the calling function block.

1. Open the function block for which you wish to call the multi-instances.
2. Drag a standard function block from the library into the network of the calling function block, for example, the communication block "TSEND_C" from the "Advanced Instructions" palette. The "Call options" dialog opens.
3. Click on the "Multi Instance" button, followed by "OK" to confirm.

Fig. 02

The called standard function block is inserted automatically as a static variable in the interface of the calling function block.

Note
In the case of function blocks you have created yourself, the "Multi Instance" button in the "Call options" dialog is grayed out and cannot be operated.

More information on multi-instances is available in the STEP 7 Basic Online Help under "Multi-instances".

Creation environment
The pictures in this FAQ were created with STEP 7 Basic version V10.5.