plc IO module de classification

Switch means only on and off (or 1 and 0) signals, analog io module two states means that changes continuously. IO commonly classified as follows: switch: by voltage level points, 220VAC, 110VAC, 24VDC, by way of sub isolation, with relay isolation and transistor isolation. Analog: divided by signal type, there is a current type (4-20mA0-20mA), voltage type (0-10V0-5V-10-10V), etc., according to the accuracy of points, there 12bit14bit16bit like. In addition to the general purpose IO, there are special IO module plc, such as thermal resistance, thermocouple, pulse and other modules. The number of points determined by IO module specification and quantity, IO module can be more or less, but the maximum number of CPU capacity can be managed by the basic configuration, namely by the maximum floor or rack slot limit.