User manual

1-Wire Application Guide v1.04 Page 36 of 41
The RS232 settings should be 9600 bps, no parity, eight bits, with no flow control.
RS232 cables should not be longer than 50 feet (about 15 meters) for proper
communication at the 9600 bps rate used.
Of course, if your PC does not have a serial port, use a USB to serial port
adapter to make the connection. Many types are available and they should all
work fine.
5.3 Trouble-shooting PC problems
As a first step to trouble-shooting PC or software problems, you want to make
sure that your PC can properly communicate with TEMP08. HyperTerminal,
which comes with every Windows based PC, can be used to monitor
communications with TEMP08. HyperTerminal is usually located in the Windows
Start folder under Accessories/Communications. Figure 25 shows what the
settings should look like (COM3 shown in this example – choose your COM port
to match the RS232 connection to TEMP08):
Once you have made the connection to a PC, and set up HyperTerminal to
properly communicate with TEMP08, make sure you can communicate with
TEMP08 by entering HLP, or any other command. You should see a response
from TEMP08 similar to what is shown in the current user manual for the
command you entered.
If you can communicate in this way to TEMP08, then shut down HyperTerminal
(to free the RS232 port for other use) and try running your software again.
If you are unable to communicate with TEMP08 with HyperTerminal, then check
the following:
1. Is the cable connecting TEMP08 to the PC a straight-through cable?
Check the wiring to make sure.
2. Is the cable plugged in properly at both ends?
3. Are the RS232 port settings properly configured (see Figure 25)?
4. Is HyperTerminal “connected”? See Figure 26 for the location of the
Connect button – click on that button to enable the connection between your PC
and TEMP08.
5. Is TEMP08 properly powered? The Green LED next to the RS232
connector should be flashing once per second. Note: it might flash red from time
to time, but that is OK.