Interfacing a PC to a UV spectrophotometer

[chem_tr]

Hello,

We have an old spectrophotometer which contains an outlet saying "printer/computer", and until now a dot-matrix printer has been attached to it. However, the printer is no longer functional, and I am thinking of interfacing an old PC to the spectrometer.

The printer was attached via serial connection (COM2), by a RS-232 cable of 9-pin "female" and 25-pin "male". I can use the same cable for interfacing, but how can I detect signals? Thing is, when the spectrometer finishes its task, we can push a button like "print graph" and the graph is sent to the printer. Can the same thing be done to a computer, but just taking the necessary values to draw a chart in Microsoft Excel, for example?

Thank you for your interest.

[Integral]

It is very likely that there is a 2 way communication code. If you send the correct signal to the device you can make it do things. You need to know what the parameters for the rs232 communication is, but more important you need to know what codes to send to the device. This will only be possible if you have access to the original documentation for the device.

If you do not have it, then maybe you can find something on the manufacturers web site.

[chem_tr]

Thank you, I guess the code includes one "stop bit", one or two "init code", etc. If so, I have a documentation of the old printer mentioning these. Is it possible to use the same settings for the computer?

[Integral]

That is the fun of RS232 communications, you need to set the basic parameters the same for both machines. As long as you can set both it is easy. If you have guess at settings on one machine it can be more fun. Documentation is essential. I can be done by trial and error, just be patient and keep trying. The commands that the device needs and how read the return messages is some thing else again.