1MRK002246-BD ABB 直流数字量输入模块

1MRK002246-BD

2.7 Digital input/output module
1. Principle of digital input/output module
(1) Principle of digital input module
The digital input module is used to connect external mechanical contacts and digital electrical signal processors, which convert electrical signals from field devices (such as transfer switches, limit switches, proximity switches, temperature sensors, electromagnetic coils, valve actuators, etc.) into a level signal that can be processed by the CPU. All I/0 modules are connected to the bus in photoelectric isolation and can be configured by software
PLC input circuit according to the type of external power supply is divided into DC input circuit and AC input circuit; According to the PLC input module common end (COM end) current flow is divided into source input circuit and leakage input circuit: according to the connection of the common end of the light emitting diode is divided into common anode and common cathode input circuit; According to the wiring mode, it is divided into manifold type, grouping type and separation type.
The I/0 circuit of the sink point has a common point, and the input point or output point shares a power supply: the I/0 circuit of the packet type is divided into thousands of groups, and the I/0 circuit of each group has a common point, and the circuit between the groups is separate, and different power supplies can be used respectively; The separated I/0 circuits are isolated from each other, and each I/0 can use an independent power supply, as shown in Figure 2-14.
Therefore, the digital input module is divided into two basic signal types: DC signal input and AC signal input