PET-2255U is an 8-channel DI (Wet/Dry Contact) and 8-channel DO (Sink-type or Source-type) module, selectable via wiring. Each input channel can function as a 32-bit counter, while each output channel can be configured with a power-on value and safe value, ensuring the module's safe operation in applications with hazardous voltages. The module includes a built-in 2-port Ethernet switch, facilitating a daisy-chain topology. This feature offers flexibility in device configuration, simplifies installation, and reduces infrastructure costs. The module features optical-isolated 3000 Vrms transient overvoltage protection and does not support channel-to-channel isolation. Additionally, the module provides EMS (FET/ESD/Surge) protection and 3000 VDC I/O isolation to enhance noise protection capabilities in industrial environments.

Moreover, the module supports I/O Pair-Connection functionality, allowing the establishment of DI-to-DO pairing connections with the remote module via Ethernet. Once configured, local DI data can be written to remote DO channels in Push mode via Modbus TCP. Alternatively, pull remote DI to local DO.

PET-2255U supports the MQTT protocol, serving as a publisher and subscriber of messages. When connected to an MQTT Broker Server, it can publish real-time statuses of I/O in the form of topics and receive messages from subscribed topics. If a disconnection occurs between the module and the broker during communication, its mechanism for reconnecting can automatically restore the connection. Additionally, its Keep-Alive Interval mechanism ensures a continuous connection with the broker.

PET-2255U supports the SNMP V2c specification, enabling it to transmit both module and I/O information to SNMP network management devices or software (SNMP Network Management Software). This allows administrators to monitor module status in real-time. Additionally, if the Trap function is enabled, the module can proactively send messages to administrators when there are changes in I/O statuses or during restarts, keeping them informed of channel statuses at all times.