Hi all, since my debut as an automation engineer I have not yet costed a programming service. I would like to know the right method to cost the programming work of the PLC and HMI:

I would like to know the right way to calculate the cost of the PLC and HMI programming work:

- Should I bill per I/O?

-Should I bill per day/hour of work?

-Should I bill the HMI prohramming per HMI view?

Tank.

S.D