Simatic Fetch/Write

  • Fetch/Write (ISO-on-TCP RFC 1006)

    The protocol Simatic Fetch/Write enables the connection of S7 automation devices with any communication partner. It provides direct access to the S7 user memory without changes in the user application itself, if applicable.

    Only a communication unit (CP) for Ethernet connection or alternatively an onboard Ethernet interface that supports ISOonTCP (RFC1006) as well as the protocol Simatic Fetch/Write must be available.

    An onboard Ethernet interface requires the development of special function modules for the communication in addition to the S7 user program. This is not necessary with an external communication unit (CP).

    ISO - OSI classification
    chart: ISO - OSI classification

    The SIMATIC® S7 series supports the services FETCH and WRITE via the protocol ISO-on-TCP only in passive mode, i.e. it operates as a server and does not establish communications links spontaneously.

    To address all internal data on the PLC side, the S7 Protocol (RFC 1006) can be used, not restricting access to data blocks (DB).

7 Application Layer Fetch Read / Fetch Write
6 Presentation Layer n/a
5 Session Layer n/a
4 Transport Layer ISO-on-TCP (RFC 1006)
TCP (RFC 793)
3 Network Layer IP (RFC 791)
2 Link Layer IP (RFC 894)
1 Physical Layer Ethernet (IEEE 802.3)
Available Protocol Stacks

Simatic Fetch/Write, Master

Applicable Products
  • ipConv

    Universal protocol converter for highest degree of flexibility

  • ipConvLite

    Universal protocol converter for small and distributed applications

  • ipConvLite/MEC2PBS

    Universal protocol converter with integrated PROFIBUS-DP, slave interface

  • ipConvLite/MEC2PBM

    Universal protocol converter with integrated PROFIBUS-DP, master interface

  • ipConvLite/MEC2PNS

    Universal protocol converter with integrated PROFINET-IO, slave interface

  • ipConvOPC

    Windows software package for universal conversion between diverse standard protocols

  • ipConv/VM

    Universal protocol conversion for VMware Workstation and VMware ESXi

  • ip4Cloud

    Link critical processes securely to IT/Cloud/SCADA services

  • ip4Cloud/SEC3PB

    Capture PROFIBUS data by eavesdropping and transmit it to Cloud/IT or SCADA services

  • ip4Cloud/SEC3IO

    Switch and monitor digital I/O states to transmit them to IT/Cloud/SCADA services

  • ipELB

    4-Port Ethernet Line Breaker with relay controlled Ethernet ports and integrated I/O module

  • ICESA S7
    ICESA S7, Spain

    Products: ipConvLite
    Protocol Stacks: IEC 60870-5-104, Slave Simatic Fetch/Write, Master

  • Simatic Fetch/Write - IEC 104
    Simatic Fetch/Write - IEC 104, Italy

    Products: ipConvLite
    Protocol Stacks: IEC 60870-5-104, Slave Simatic Fetch/Write, Master