Waveshare Guide-Type 4-Way RS485 High-Current Relay Module, Modbus RTU Protocol Features: 1. Support setting device address (1-255) to cascade multiple devices through RS485 bus 2. With flash-on and flash-off functions, the relay can be controlled by command to automatically close after being turned on for a period of time 3. Onboard voltage regulator chip, direct plug-in 7V-36V wide voltage power supply 4. Onboard integrated power isolation, which can provide stable isolation voltage, and no additional power supply is required for the isolation end 5. Onboard integrated ADI magnetic coupling isolation, which can be used for signal isolation, high reliability, strong anti-interference, low power consumption 6. Onboard resettable fuse and TVS (transient voltage suppressor) can effectively suppress surge voltage and transient spike voltage in the circuit, prevent overcurrent and overvoltage, lightning protection and anti-static 7. Onboard optocoupler isolation to avoid interference from relay high-voltage circuit 8. Adopting dedicated relay driver chip with built-in freewheeling diode protection, the driving capability is stronger and more stable 9. Onboard anti-reverse connection circuit to avoid reverse connection of positive and negative poles and burnout of circuit 10. Adopting high-quality high-current relay, load connection is allowed: less than or equal to 30A 250V AC or less than or equal to 30A 28V DC 11. Guide rail ABS protective shell, easy to install and use, safer with shell 12. External 3 LED indicators, convenient to check MCU status and signal receiving and sending status Product parameters: 1. Working voltage: 7V-36V 2. Communication protocol: RS485 3. Communication baud rate: 4800, 9600, 19200, 38400, 57600, 115200, 128000, 256000 4. Default communication format: 9600, N, 8, 1 5. Number of relays: 4 6. Contact type: one normally open, one normally closed 7. Contact load: less than or equal to 30A250VAC or equal to 30A28VDC 8. Communication protocol: standard