The robustness and availability of network communication equipment directly determine the lifeline of the entire automation system in rail transit, power substations, and harsh industrial manufacturing sites. When old unmanaged switches face replacement due to bandwidth bottlenecks or insufficient environmental tolerance, engineers often need a modular device that can provide high-density ports, achieve millisecond level network redundancy, and comply with strict environmental certifications. The Hirschmann MICE MS20/MS30 series industrial Ethernet switches are professional grade products designed to address communication challenges under extreme conditions.
This article will provide you with a highly practical and in-depth technical guide from the dimensions of modular hardware architecture, redundant power supply and ring network topology, explosion-proof area safety regulations, and common on-site troubleshooting.
Modular hardware architecture and thermal management
The biggest feature of the MICE (Modular Industrial Communication Equipment) series is its modular design with a "building block" approach. Its basic module integrates switching function, management function, redundancy control, display control, and voltage access; The physical interface for connecting to the local area network is provided by pluggable media modules.
Model positioning differences:
MS20: Provides up to 8, 16, or 24 10/100 Mbit/s Ethernet ports to meet medium density access requirements.
MS30: On the basis of MS20, it supports up to 2 additional gigabit (1000 Mbit/s) ports, suitable for backbone networks with high bandwidth uplink requirements.
During on-site installation, heat dissipation management is the first threshold to ensure long-term stable operation of the equipment. The device adopts a fanless design and relies on a metal casing for natural heat dissipation. During installation, standard 35mm DIN rails must be used to ensure that there is at least 10 cm (4 in) of space left above and below the equipment to maintain good air circulation. If multiple high-power devices are densely installed in the control cabinet, it is recommended to add fans or air conditioners inside the cabinet to avoid heat accumulation and accelerated aging of internal components.
Power supply logic and redundancy mechanism: details that cannot be ignored
In industrial sites, the stability of the power supply system directly affects communication. The power supply design of MS20/MS30 is very rigorous, but it is prone to pitfalls when wiring:
SELV/PELV mandatory requirement: Equipment must be connected to Extra Low Voltage (SELV) or Protective Extra Low Voltage (PELV) circuits that comply with IEC 60950-1 or IEC/EN 62368-1 standards. For the North American market, it is necessary to connect a power supply that complies with the National Electrical Code (NEC) Class 2 standard, with a maximum output power limit of 100W.
Dual redundant power supply: The basic module provides two independent 4-pin terminal blocks (or one 6-pin terminal block), supporting dual power supply redundant access. The two inputs are internally decoupled and do not have equal current distribution. When one of the power sources has a high voltage, the equipment is completely powered by that source; Once the circuit loses power, the other circuit seamlessly takes over. If only one power source is connected on site, the equipment will report a "power failure" alarm. To eliminate this alarm, you need to block the event in the management interface or connect both power sources.
Grounding specification: When supplying DC power, only the negative pole (0V) of the voltage input is allowed to be grounded. The bottom panel of the device is grounded through DIN rails, and independent grounding screws can be used for dual grounding protection. If using AC power supply (specific model), it is necessary to ensure that the power supply is isolated from ground potential.

Practical application of redundant ring network and DIP switch configuration
In industrial networks, a single point of disconnection may cause the entire production line to shut down. The MICE series supports redundant ring network technology based on HIPER Ring. The core of the configuration lies in the DIP switch at the bottom of the basic module (4-pin or 3-pin, depending on the model).
RM (Redundancy Manager) switch: Turn the switch to ON to enable the redundancy manager function.
Ring Port switch:
For MS20, the ON state indicates that port 1 of module 1 and port 1 of module 2 are used as ring network connection ports.
For MS30, the ON state indicates that port 1 and port 2 of module 2 are used as ring network connection ports.
Stand by switch: In the dual loop redundant coupling scenario, set this device as a backup coupling node.
When configuring, if the RM indicator light remains green and constantly on, it indicates that the redundancy function is normal; If it shows a constant yellow light, it indicates that the redundant port has been activated (i.e. there is a breakpoint in the ring network and data is being transmitted from the backup path); If it flashes green, it usually means that the HIPER Ring configuration is incorrect (such as the Ethernet cable not being properly connected to the specified port).