Numpad

hello mates, im here new. i hv question, i hope someone can help me
I want to use a numpad with my PLC (Siemens S7-200). The user inputs a password (with 4 chr), if the password is correct then the door will open automatically. but first, i want to learn how can I use numpad with PLC? thanks.

Any input device must be compatible with the PLC that you are using (Siemens S7-200). See the Number Pad user manual to find out which PLCs it will work with. If it is compatible with the Siemens, then read farther in the instruction manual to find out how to use it.

Or use a siemens TD HMI Text Display screen they are pretty cheap and made specifically for the S7-200 series