These blocks initialize and control communication between ibaPDA and the S7-1500 controllers.

The ibaREQ3sym block family allows access to both optimized and non-optimized data blocks. Addressing is done by using only the symbol names.

The ibaREQ3sym module family is the recommended access variant as of TIA Portal V19. With this version, runtime optimizations are possible, such as the outsourcing of the cyclical reading of the actual values from the ibaREQ3sym_M block. Therefore, the individual blocks can be specifically distributed across different call levels.

One set of Request blocks has to be called for each Request module (connection) in ibaPDA. The blocks used are part of the iba S7 library, see iba S7 library.

Note
	Only use Request blocks from the latest iba S7 library! Request blocks in application examples can be outdated and, thus, cause errors.

Use different Request block combinations depending on the current system configuration:

• ibaREQ3sym_M (Management) The block realizes the communication with ibaPDA. Ideally, the block is called in OB1 or lower-priority OB.

• ibaREQ3sym_NetE_dc (Provision and buffering of current signal values) The block provides the current signal values and buffers them. Ideally, the block is called in the OB in which the data is updated.

• ibaREQ3sym_NetE_send (sending of current signal values) The block buffers the current signal values and sends them to ibaPDA. The block is called in OB1 or a cyclic interrupt OB at the required send interval.

• ibaREQ3sym_PN (provision and sending of current signal values) The block provides the current signal values using the transmission cycle. Ideally, the block is called in a cyclic interrupt OB at the required send interval.

• ibaREQ3sym_DB_PDA (DB interfaces) This DB acts as an interface to ibaPDA and between the different Request blocks.