Features: Version 1 (N4A8I16) 4-channel 0-20MA current analog input, 2-channel 0-10V voltage analog input, 2-channel 0-30V voltage analog input, 4-channel photoelectric isolation switches input (compatible with NPN), 16-channel 300MA Darlington tube output (can directly drive relays solenoid LED). Version 2 (N4A7K16) 7-channel 0-20MA current analog input, 1-channel 0-30V voltage analog input, 4-channel photoelectrically isolated switches input (compatible with NPN), 16-channel 300MA Darlington tube output (can Direct Drive Relays Solenoid LED). Support standard Modbus RTU command, function code: write 05/06/15/16 read 01/02/03/04. With hardware factory settings function, with TVS anti-surge protection. In MODBUS command, it can support up to 64 devices in parallel. The default baud rate is 9600BPS, the baud rate can be selected by command 2400 4800 19200 38400 57600 115200BPS. You can choose the parity is no parity, even parity and odd parity. You can set the data sending return time, the maximum can be set to 1000ms. Specifications: Working voltage: DC7-25V (DC9V 12V 24V) Working current: 12-20MA Style: N4A8I16 only board, N4A8I16 with DIN rail housing, N4A7K16 only board, N4A7K16 with DIN rail housing(optional) Package Includes: 1PC Acquisition Module note: Please allow 0-1cm error due to manual measurement. make sure not mind before bid. Due to the differenceS between different monitors, the picture may not reflect the actual of the item.