Select the output module plc switch output module

The output module is required for the internal drive signal to PLC low voltage signal is converted to an external output device. The main selection should consider the type and size of the load voltage, the system latency requirements, whether state and frequent load changes.
1. Select the output mode
Digital output module has three output modes: output module plc relay output, thyristor output and transistor output. Relay outputs are cheap, both to drive an AC load, but also for the DC load, but  Programmable Output Module also for a wide range of voltage magnitude, a small voltage drop, and the ability to withstand strong transient over-voltage and over-current. But it belongs to have contact elements, its movement is slow, short life, poor reliability, and therefore, does not only apply to frequent on-off occasions. When used to drive inductive load, output module plc operating frequency does not exceed its contacts 1Hz.
For frequent load off, you should use triac output or transistor output, they are non-contact components. But only for analog output module  Triac output AC load, and transistor output can only be used for DC load.
2. Select the output wiring of different output wiring of the PLC, are generally grouped outputs and two separate outputs, outputs are grouped several output points as a group, sharing a common terminal between the groups are separated , respectively, using a different power. And each output point delimited output has a common, mutual isolation between the outputs, each output point may use a different power source. The main species Programmable Output Module  should be based on how much power the system load may be. General Integral PLC outputs both groups, there are also separate output.