Industrial Network Switch Symbol
Definition: The Industrial Network Switch symbol represents a managed or unmanaged Ethernet switch used in industrial automation and control networks to interconnect PLCs, HMIs, sensors, and other field devices on a common LAN segment, depicted as a rectangular module block with multiple labelled Ethernet port pins.
Also known as: Ethernet switch, industrial Ethernet switch, SCALANCE switch, managed switch, network hub.
What the Industrial Network Switch symbol means
The Industrial Network Switch symbol denotes a layer-2 Ethernet switching device designed for harsh industrial environments. Unlike consumer switches, industrial variants support DIN-rail mounting, wide temperature ranges, redundancy protocols (RSTP, PRP, HSR), and managed VLAN configuration, all of which are captured by showing the switch as a structured block in a network topology diagram.
In wiring and network diagrams the symbol appears as a rectangular block labelled with port identifiers (Port 1–4, Uplink). It conveys that each port provides a full-duplex 100/1000 Mbit/s Ethernet connection and that all ports share a common switching fabric, enabling deterministic communication between connected industrial devices.
How to identify the Industrial Network Switch symbol
The Industrial Network Switch symbol is drawn as a rectangle with multiple port pins along the bottom edge (Port 1, Port 2, Port 3, Port 4, Uplink) and a power supply connection implied or labelled separately. The block may carry a switch or network icon, and port labels use standard Ethernet naming. The multiple-port arrangement and 'switch' or 'SW' label distinguish it from a single-port network interface or a simple bus.
Function in a circuit
An industrial network switch examines each incoming Ethernet frame's MAC address and forwards it only to the port connected to the destination device, reducing network collisions and segmenting traffic. Managed variants add VLAN tagging, QoS prioritisation, SNMP monitoring, and ring-redundancy protocols (RSTP) to meet the real-time and fault-tolerance requirements of industrial control systems.
Standards: IEC vs ANSI
| IEC 60617 | IEC 60617 does not define a dedicated symbol for network switches; they are represented as functional blocks per IEC 81346 (industrial systems structuring). IEEE 802.3 governs the Ethernet physical and data-link layers. |
|---|---|
| ANSI/IEEE 315 | ANSI Y32.2 / IEEE 315 has no specific switch glyph; network equipment is drawn as labelled rectangle blocks following IEEE 315 assembly-block conventions. IEEE 802.1Q covers VLAN tagging used by managed industrial switches. |
| Key difference | Both IEC and ANSI/IEEE represent the device as a generic module block; port count and label style are the only differentiators between vendor representations. |
Terminals / pins
| Pin | Name |
|---|---|
| p1 | Port 1 |
| p2 | Port 2 |
| p3 | Port 3 |
| p4 | Port 4 |
| uplink | Uplink |
Typical values
Port speeds: 10/100 Mbit/s (Fast Ethernet) or 10/100/1000 Mbit/s (Gigabit Ethernet). Supply voltage: 24 V DC (typical industrial); some models accept 12–48 V DC or 100–240 V AC. Operating temperature: −40 °C to +70 °C (industrial grade). MTBF: typically > 200 000 hours.
Where the Industrial Network Switch symbol is used
- PLC networks connecting multiple Siemens S7 or Allen-Bradley PLCs to a supervisory SCADA system via PROFINET or EtherNet/IP
- Factory automation cells linking robotic arms, servo drives, and HMI panels on a common industrial Ethernet ring
- Building automation systems connecting BACnet/IP devices such as VAV controllers, chillers, and fire panels
- Power substation automation networks using IEC 61850 GOOSE messaging between protection relays and bay controllers
- Machine safety networks where the switch enforces VLAN separation between safety-rated and standard control traffic
- Remote field cabinets where a DIN-rail-mounted switch aggregates sensor data for transmission to the central control room
Example
In a PROFINET machine-control network, a Siemens SCALANCE X208 industrial switch connects a PLC CPU (Port 1), an HMI panel (Port 2), two servo drives (Port 3, Port 4), and the plant backbone network (Uplink). The switch enforces RSTP ring redundancy so that a single cable fault causes less than 1 ms network recovery, maintaining motion-control determinism.
Key facts
- An industrial network switch forwards Ethernet frames based on destination MAC address, operating at OSI Layer 2, and provides full-duplex operation on each port to eliminate collisions.
- Industrial switches are rated for −40 °C to +70 °C operation, DIN-rail or panel mounting, and 24 V DC power supply to suit industrial control cabinet environments.
- Managed industrial switches support RSTP (IEEE 802.1D-2004) and optionally PRP/HSR (IEC 62439-3) ring-redundancy protocols, enabling sub-millisecond failover for high-availability control networks.
- The symbol has five pins in schematic representations: Port 1, Port 2, Port 3, Port 4, and Uplink, each representing a 100/1000 Mbit/s RJ-45 Ethernet interface.
- VLAN segmentation (IEEE 802.1Q) on managed industrial switches isolates safety-critical traffic from standard process data, reducing the risk of broadcast storms disrupting safety functions.
- Common industrial Ethernet protocols carried by these switches include PROFINET (IEC 61158-6-10), EtherNet/IP (ODVA), Modbus TCP (IEC 61968), and IEC 61850 GOOSE.
- Power consumption is typically 3–10 W for a 5–8 port Fast Ethernet switch; the 24 V DC rail is protected by a blade or electronic fuse in the control cabinet.
Diagrams that use this symbol
Frequently asked questions
What does the industrial network switch symbol mean in a wiring diagram?
The Industrial Network Switch symbol represents a Layer-2 Ethernet switching device that interconnects PLCs, HMIs, and other industrial devices on a shared Ethernet network. It shows that all connected ports share a switched backplane, enabling addressed point-to-point communication rather than a shared bus collision domain.
What does the network switch symbol look like in a schematic?
The Industrial Network Switch symbol appears as a rectangular block with port labels (Port 1–4, Uplink) along the bottom edge. A switch icon or the abbreviation 'SW' may appear inside the block. Power supply connections are either labelled separately or implied by the enclosing cabinet power rail.
How many ports does the industrial network switch symbol show?
The symbol in this schematic library shows five ports: Port 1, Port 2, Port 3, Port 4, and an Uplink port. Physical industrial switches are commonly available with 5, 8, 16, or 24 ports; the symbol is a representative abstraction.
What is the difference between a managed and unmanaged industrial switch?
An unmanaged industrial switch forwards frames based on MAC addresses with no configuration capability — suitable for simple point-to-point connections. A managed switch adds VLAN, QoS, RSTP redundancy, SNMP monitoring, and port mirroring, which are required for complex industrial control networks with determinism and fault-tolerance requirements.
What standard governs industrial Ethernet switches?
IEEE 802.3 governs the Ethernet physical and data-link layers. IEEE 802.1D and 802.1Q cover RSTP spanning-tree and VLAN tagging. IEC 62439-3 defines PRP and HSR ring-redundancy protocols. For PROFINET-specific switch requirements, IEC 61158-6-10 applies.
What supply voltage do industrial network switches use?
Most industrial network switches are powered from a 24 V DC supply, which is the standard industrial control cabinet voltage. Some models accept a 12–48 V DC range, and rackmount versions may use 100–240 V AC. The 24 V DC feed is typically fused at 1–2 A in the cabinet power distribution.
What PROFINET devices connect to an industrial switch?
PROFINET devices connected to an industrial switch include Siemens S7 PLC CPUs (as PROFINET IO controllers), distributed I/O modules (e.g., ET 200SP), HMI panels, servo drives (SINAMICS), and engineering workstations running TIA Portal. The switch carries PROFINET real-time (RT) and isochronous real-time (IRT) frames between these devices.
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