What is the PLC protocol

ADwin-Interface to the S7-PLC

Communication via Ethernet

The Simatic Fetch / Write communication via the Ethernet network is a one-to-one connection between an ADwin system and a Simatic PLC. The connection enables read and write access to the Simatic system memory areas. There are access options to data blocks, flags, inputs, outputs, counters and timers.

As a client, the ADwin system is the active part of communication. From the point of view of the Simatic S7, it is a passive communication function that only needs to be configured. The PLC cannot access the ADwin system.

Requirements for access to Simatic-PLC:

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

Function in ADwin

In an ADbasic process, communication with the PLC is controlled by a global parameter. The send and receive data as well as the configuration data for communication are stored in global arrays.

Configurable parameters:

  • Field numbers for send and receive data
  • Number and start address of the data to be transferred
  • Network configuration of the PLC: IP and port numbers
  • Type of system block (DB, marker, etc.)
  • TCP / IP timeout and polling time

Additional Information ( pdf, 270 kB)