1. Internal impedance: 3.3kΩ
2. Accept 12–30V voltage input
3. This terminal is bi-directional input
terminal and supports NPN/PNP
connection modes
4. Max. input frequency: 1kHz
5. All are programmable digital input
terminals, and users can set the terminal
function via function codes
Besides S1–S8 functions, it can also act as high frequency pulse
input channel
Max. input frequency: 50kHz