Description
SiboTech MEC-325 | EtherNet/IP Modbus Gateway
Product Introduction
The SiboTech MEC-325 is an industrial communication gateway used to connect serial equipment to an EtherNet/IP control network. Its serial side supports Modbus master operation as well as a general-purpose transparent mode, while the Ethernet side operates as an EtherNet/IP interface. This makes the unit applicable when an existing meter, controller, instrument, scanner, or other serial device must exchange data with an EtherNet/IP PLC without replacing the field device.
For control-system integration, the MEC-325 provides two 10/100 Mbps Ethernet ports with an integrated switch and a single serial channel configurable for RS-485 or RS-232. In Modbus-master operation, up to 100 Modbus commands can be configured, with support for function codes 01H, 02H, 03H, 04H, 05H, 06H, 0FH, and 10H. EtherNet/IP cyclic data capacity is specified at up to 492 bytes input and 492 bytes output in the applicable Modbus mode.
MEC-325
Key Technical Specifications
- Model: MEC-325
- Manufacturer: SiboTech
- Gateway Type: EtherNet/IP / serial communication gateway
- EtherNet/IP Role: EtherNet/IP adapter/device
- Serial Protocol: Modbus master or general-purpose/transparent serial mode
- Serial Interface: RS-485 or RS-232
- Serial Baud Rates: 1,200 to 115,200 bps selectable
- Modbus Commands: Up to 100 configurable commands
- EtherNet/IP Input Data: Up to 492 bytes in Modbus mode
- EtherNet/IP Output Data: Up to 492 bytes in Modbus mode
- Ethernet Ports: 2 × 10/100 Mbps adaptive ports, integrated switch
- Supply Voltage: 24 VDC nominal; 11–30 VDC operating range
- Typical Current: 70 mA at 24 VDC
- Operating Temperature: -40°C to +60°C
- Relative Humidity: 5–95%, non-condensing
- Dimensions: 25 × 100 × 90 mm
- Mounting: 35 mm DIN rail
- Enclosure Rating: IP20
The manufacturer documentation also specifies IP-address conflict detection and byte-swapping support for applicable Modbus data functions, which can be important when integrating serial equipment with different word/byte ordering conventions.
Application Scenarios & Pain Points
1. Legacy Serial Device → EtherNet/IP PLC
A machine may still rely on a serial meter, instrument, scanner, or controller while the supervisory PLC uses EtherNet/IP. Replacing the field device solely to obtain Ethernet connectivity can introduce unnecessary commissioning and validation work.
The MEC-325 provides the protocol boundary between the existing serial device and the EtherNet/IP controller.
2. Modbus RTU Equipment on a Rockwell-Based Network
For Modbus master applications, the MEC-325 supports configurable commands and common Modbus function codes including 03H, 04H, 06H, and 10H. This allows register-based field data to be mapped into the EtherNet/IP side without adding a dedicated serial communication module to every PLC system.
3. Multi-Device Ethernet Network Layout
The two 10/100 Mbps Ethernet ports use an integrated switch and logically operate as one Ethernet interface/IP address. This can simplify physical network wiring where the gateway is installed inline with other Ethernet equipment.
4. Transparent Serial Integration
The general-purpose serial mode supports character timeout, character-count, and delimiter-based controls. This is useful when the connected serial equipment does not use standard Modbus framing.
QA & Live Testing SOP
For a used or surplus , procurement inspection should verify the exact hardware revision before installation.
- OEM Identity Check
- Confirm the front-panel designation.
- Verify manufacturer labeling and serial/hardware identification.
- Photograph all labels before energization.
- Mechanical Inspection
- Check DIN-rail mounting mechanism.
- Inspect RJ45 connectors and serial terminals for mechanical damage.
- Check the enclosure for cracks, deformation, corrosion, or contamination.
- Power-Up Test
- Apply controlled 24 VDC within the documented 11–30 VDC range.
- Verify normal startup indications and absence of abnormal heating.
- Do not substitute an unverified power supply polarity or wiring arrangement.
- Ethernet Test
- Connect one Ethernet port to a controlled test network.
- Verify link negotiation at 10/100 Mbps.
- Confirm IP configuration and network visibility.
- Serial Communication Test
- Verify the configured RS-485 or RS-232 interface.
- Test representative baud rate, parity, and stop-bit settings.
- For Modbus operation, exercise read/write commands against a controlled simulator or known-good slave.
- EtherNet/IP Test
- Import the appropriate EDS/configuration information where required.
- Establish an EtherNet/IP connection with a compatible controller or test environment.
- Verify expected input/output data exchange.
- Packaging
- Use ESD-safe handling and packaging.
- Protect RJ45 and serial connectors against mechanical impact.
- Preserve configuration information with the unit when available.
The manufacturer documentation specifically provides configuration software and EDS resources for variants, so configuration files and firmware/version information should be retained during procurement and replacement testing.
Field Engineer’s Pitfall Guide
❗ Do not assume the serial port is automatically RS-232. The supports RS-485 or RS-232 configurations, and the actual hardware/configuration must be verified before wiring.
❗ Do not treat the two Ethernet connectors as two independent IP interfaces. The documented architecture uses an integrated switch; logically, the ports operate as one Ethernet interface/IP.
❗ Check the actual firmware/version before replacing an installed unit. Manufacturer documentation identifies multiple versions, and configuration software/EDS compatibility can depend on the applicable hardware or firmware revision.
❗ Check serial framing before troubleshooting the PLC. Baud rate, parity, stop bits, RS-232/RS-485 selection, slave addressing, and Modbus command configuration can all prevent valid communication even when the Ethernet link is healthy.
❗ Do not confuse the maximum EtherNet/IP data size with the number of Modbus registers available in every configuration. The documented 492-byte input/output limits apply to the applicable Modbus operating mode and should be evaluated against the actual configured command/data map.
Intent-Driven FAQ
What is the SiboTech used for?
The is an industrial gateway that connects serial equipment using Modbus or general-purpose serial communication to an EtherNet/IP network.
Does support Modbus?
Yes. The serial side supports Modbus master operation. The documented Modbus implementation supports function codes including 01H, 02H, 03H, 04H, 05H, 06H, 0FH, and 10H.
Does support RS-485?
Yes. The serial interface can support RS-485; RS-232 is also supported depending on the configuration. Verify the actual unit and wiring requirements before installation.
How many Ethernet ports does have?
The has two 10/100 Mbps adaptive Ethernet ports using an integrated switch architecture. The two ports logically operate as one Ethernet interface/IP.
What power supply does require?
The documented supply is 24 VDC, with an operating range of 11–30 VDC and approximately 70 mA consumption at 24 VDC.
What is the maximum EtherNet/IP data size?
The documented maximum is 492 bytes of input data and 492 bytes of output data in the applicable Modbus operating mode. General-purpose mode has a lower documented limit of 254 bytes including the check bytes.
Can replace an existing gateway directly?
Not automatically. Verify the existing gateway’s EtherNet/IP assembly mapping, serial interface type, firmware/version, baud rate, Modbus command map, IP configuration, and PLC configuration before treating the as a drop-in replacement.
What should I verify before buying a used ?
Confirm the OEM model marking, hardware/firmware revision, physical condition, serial interface configuration, Ethernet ports, power input, configuration software/EDS compatibility, and successful communication testing. For an installed replacement, compare the existing PLC EtherNet/IP configuration and serial data map before commissioning.
