>I need to develop program which will connect PC an AU400 chemistry analyzer (blood analyze). Machine is connected to PC wia serial to ethernet device. Goal is to gather blood sample analyzes from machine and process data.
>I've never done something like that before (sending and reeading hex commands to serial port); only different type of scales. In attachment is manual I have.
>I would appreciate any help (if possible with examples).

If your task is life-critical:

- It may be subject to government regulations
- You may be required to have liability insurance
- Even if there are no applicable regulations, you should follow very strict development processes which go far beyond those required for business software

One example of life-critical: if your software makes a mistake and records a "normal" result for an abnormal sample, that might leave a patient untreated, with potentially life-threatening consequences.

Does the maker of the AU400 device offer software to do this task? If so you should probably be using that instead, even if it's expensive.

By coincidence, another active member here (Dragan Nedeljkovich) is only about 50km from you as the crow flies.