Ethernet Communication

The Simatic Fetch/Write communication via Ethernet network is a point-to-point connection between an ADwin system and a Simatic PLC. The connection enables write and read-only access to the system memory of the Simatic PLC. Access is available to data modules, flags, inputs, outputs, counters and timers.

The ADwin system is the client which runs the active part of communication. Seen from Simatic S7, the communication function is passive and needs to be configured only. The PLC cannot access the ADwin system.

Requirements for access to a Simatic PLC:

• ADwin system with Ethernet interface ENET2, current firmware, and bootloader option.
• Simatic PLC with Communication Processor (CP), which supports the Fetch/Write protocol.
• Two configured network connections on the PLC, one for Fetch and one for Write.

ADwin functions

In an ADbasic process, a global parameter controls the communication with the PLC. The sent and received data as well as the configuration data for commuication are stored in global arrays.

Parameters to be configured:

• Array numbers for sent and received data.
• Number and start address of data to be transferred.
• Network configuration of the PLC: IP and port numbers.
• Type of system module (DB, flag etc.).
• TCP/IP timeout and polling time.

Further information ( pdf, 270 kB)