Ok...I figured out how to input strings into the PLC via the serial port using HyperTerminal. In retrospect, it was really easy to do
. The problem now is that whenever the PLC is freshly reset, and I input a string "test", for example, the PLC received a bunch of garbage strings before receiving the input strings, after these strings are received, the strings are input normally. My TBasic program reads the input string, outputs it into the LCD screen and writes the same string back to the HyperTerminal. The garbage strings are always the same, here is a transcript of my HyperTerminal communications:
test <----- my input
1WF8 48* <----- Garbage strings, displayed on LCD
@01WF9 49* <----- and sent back to HyperTerminal
@01CL4E* <----- line by line.
@01C133* <-----
@01CL4E* <-----
test <----- My string returned from the PLC
After this initial weirdness, input/output works fine and the garbage strings do not re-appear unless the PLC is reset again. Is there any way to avoid this confusion?
-Gene