Modbus Server provides a Modbus TCP server (and RTU slave as of V3.0) for testing Modbus clients. It simulates a Modbus device with registers.
Modbus TCP Server and RTU Slave simulates Modbus Holding, Input and Output registers 0 to 65535 according to Modbus specification 1.1b3. Simulate Modbus devices to facilitate software development and observe raw data exchange between TCP server and client or RTU master and slave. This version can simulate error replies, supports up to 8 simultaneous client connections and unlimited Modbus transactions.