We're having a problem regarding the pin configuration of hc900. we tried to connect the PLC to a laptop computer using a serial cable but it didn't work. Is the pin config the same as other PLC? Or config in the program?

 

If you have the 1st generation processor with the 9-pin connector you need a null modem cable.

If you have the 2nd generation processor with the 2 green terminal blocks you need to connect to the S1 port. The pinout looks like this:

PC HC900

2 - 2
3 - 3
5 - 1
4&6 (tied together)
7&8 (tied together)