PLCs, Power Supplies & Others

This module enables seamless data exchange between control processors and field devices. It supports both RS-232 and RS-485 serial communication protocols for maximum flexibility. Engineers utilize this unit to bridge legacy equipment with modern automation networks. The design prioritizes reliable data transmission in electrically noisy industrial settings. Its compact housing fits standard backplane slots without requiring additional mounting hardware.

Communication Protocol Support

The 45C28 handles asynchronous data rates from 300 baud up to 19.2 kbps. It supports popular protocols including Modbus RTU, DF1, and generic ASCII formats. Each port operates independently with separate baud rate and parity settings. This flexibility allows simultaneous connection to different device types on each channel. Consequently, system integrators can consolidate multiple communication tasks into a single module.

Physical Port Configuration

The module provides two 9-pin D-sub connectors on its front faceplate. One port supports RS-232 signaling with full handshaking lines. The other port offers RS-485 differential signaling for multi-drop networks. Each connector includes built-in transient suppression diodes for surge protection. Additionally, termination resistors are selectable via onboard jumpers for RS-485 networks.

Electrical Characteristics and Isolation

The 45C28 incorporates 500 VDC isolation between the backplane and each communication port. This isolation prevents ground loops from corrupting data transmission. The module draws a maximum supply current of 250 mA from the 5 VDC backplane. Each port provides a 5 VDC output at 100 mA for powering external converters. This feature simplifies connection to optical isolators or signal repeaters.

Physical Dimensions and Mounting Details

This module measures 12.7 cm in width, 25.4 cm in height, and 20.3 cm in depth. It weighs approximately 0.9 kg, which ensures secure seating in the backplane rack. A steel enclosure provides electromagnetic interference shielding for sensitive circuitry. The unit mounts directly into any standard 19-inch rack or compatible PLC chassis. Its front panel layout places all connectors and indicators within easy reach.

Internal Components and Memory Resources

The printed circuit board contains one microcontroller, two UART chips, and six optocouplers. A 128 kB flash memory stores firmware and configuration parameters persistently. The module also includes 32 kB of RAM for data buffering during transmission. These memory resources handle burst data transfers without losing incoming messages. Moreover, a watchdog timer resets the module automatically if communication stalls.

Status Indication and Diagnostics

Three front-panel LEDs display power, transmit, and receive activity for each port. Green LEDs indicate normal communication while amber LEDs signal data flow. The module also provides diagnostic counters through the backplane interface. These counters track CRC errors, framing errors, and overrun events. Maintenance personnel can use this data to troubleshoot network issues efficiently.

Environmental Ratings and Durability

The 45C28 operates reliably in temperatures ranging from 0°C to 60°C. It withstands humidity levels up to 95% without condensation affecting performance. The module complies with IEC 61000-4-2 for electrostatic discharge immunity. Vibration resistance meets IEC 60068-2-6 standards for industrial environments. This robust construction ensures long-term operation in manufacturing facilities.

Technical Data Sheet – Reliance Electric 45C28

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