RS232 communication problems
RS232 links between computers are notorious for giving difficulties, because there is no completely accepted international standard for them. If you are getting error messages which indicate the link is not working properly, then the difficulties may occur in a number of areas.
•The physical connections (the comms cable, the computer serial ports) may be incorrect or defective.
•The RS232 data parameters of the sending and receiving computers must be matched. (SunData takes care of the Baud rate, parity, and other data bit settings for you, so this should not be the problem).
•Even if the above settings and connections are correct, the computers may be sensitive to the exact order in which components are plugged in and the programs run.
Try the following systematic process to resolve problems:
♦Exit from the SunData programs and disconnect the comms cable from the Workabout and PC.
♦Switch off the Workabout and the PC.
♦Work through the instructions above again exactly in the order they are presented, double checking the physical connection of the comms cable and the COM port setting of your PC. Preferably work in DOS only.
The above instructions have worked successfully on a variety of portable and desktop computers, with processors from 286s to Pentiums, and DOS versions from 4.0 to 6.2.
If you still have difficulty, try making the connections in a different order, or try different PCs if they are available, or contact your agent or supplier, or
Conclusion of the Tutorial
By now you have used the SunScan to take practice readings in the emulator mode, and you have set up the configuration to take readings with the probe itself in a variety of modes (PAR, LAI and All). You have stored readings and been able to review the data file and transfer it to the hard disk of your PC. These are the basic operations which should enable you to explore other capabilities (such as the Autolog mode, for example) without further detailed instruction.
If you are now keen to think about the practicalities of your next experiment then skip to the section on Measurement Options. If not, you could consolidate your familiarity with the Workabout and its file handling concepts in the next sections.
28 • SunScan Tutorial | Document code: |
