Hongfa safety relay modules are designed with redundancy, interlocking design and built-in self-test function to ensure that the products can reliably realize the safety function in the equipment and system. The product is used to monitor the emergency stop button, safety door, light curtain/grating and other safety signal inputs, the unit module has multiple control contacts and can be expanded through the expansion module to expand the number of control channels infinitely; the product has a short-circuit cross-monitoring function between the channels or without short-circuit cross-monitoring function optional; the LED lights to indicate the internal relay operating status and power supply status.