WEG DWE-3 Electronic Motor Protection Relay with RS-485 Modbus

The WEG DWE-3-S3-MT-RS is the RS-485 Modbus RTU communication variant of the DWE-3 electronic motor protection relay, optimised for integration with Saudi industrial plant DCS, PLC, and SCADA systems via standard RS-485 serial communication. In Saudi petrochemical, oil and gas, and utilities facilities, the Modbus RTU protocol over RS-485 is the most widely used communication standard for field device integration, supported by all major DCS platforms (Honeywell, Emerson, ABB, Yokogawa) present in Saudi Aramco and SABIC facilities.

Modbus RTU Integration

The DWE-3-S3-MT-RS communicates at configurable baud rates from 2400 to 115200 bps on RS-485 two-wire or four-wire networks. Up to 247 relay addresses can be networked on a single RS-485 segment, enabling cost-effective integration of multiple motor starters into a single MCC communication network. The Modbus register map provides access to: three-phase current values (instantaneous and average), thermal state percentage, time to trip, time to reset, fault code (last fault type), and protection set points (read/write). Saudi Aramco DCS standards require Modbus RTU for field device integration in production support facilities, making the DWE-3-S3-MT-RS the standard choice for non-critical medium motor protection with DCS connectivity.

Protection Functions

All standard DWE-3 protection functions are included: Class 10 overload, phase unbalance, phase loss, thermistor input (PTC), locked rotor detection, excessive starting time, and restart inhibit (thermal memory). The 11 kW to 630 kW motor coverage range makes this relay suitable for the broad range of medium and large motors found throughout Saudi industrial MCCs including cooling water pumps, process compressor auxiliaries, plant air systems, and materials handling drives.

Saudi Deployment and Razz Support

Razz Middle East stocks DWE-3-S3-MT-RS relays for immediate delivery and provides configuration services including Modbus address mapping, baud rate setting, and DCS tag documentation per Saudi project standards. Our team supports factory acceptance testing (FAT) of MCC panels incorporating DWE-3 relays, including Modbus communication testing to the project DCS simulator.