WPD-CL520 environment control module is one of the common use interface equipment in control system. Equipped with 8 channel independent weak eletricity relays output, 8 channel digital input, 8 channel infrared output, each channel input output interface has corresponding guiding lights real time instruct its work status. Two RS-232 test and control serial communicate interface: CONTROL IN is use for interface machine and main control equipment conmunications, CONTROL OUT is used for level unite with next interface machine. The equipment's control code is four bytes same length condense instruction, all control code are open, adopt the agreement with computer compatible baudrate and communications (RS-232 standard asynchronism serial communications), it is applicable to any kinds of control system. Use the special debug software can directly realize the online debugging to SRP-ECM8, then can economize programming and time debugging.