Hi.
We have a 10kw microFIT solar system in Ontario, Canada. It has a PLC that moves the Solar Panels based on time of day.
I don't know the PLC brand - all that is marked on the PLC is "Can - Track Solar Tracking System". There is a MODE LED and a POWER LED. Input is a POT which senses the position of the panels (based on resistance), and 12vdc. Output is 6 wires controlling 3 relays, which move the panels based on time of day. There is a COM port (DB9) on the PLC.
We have found an old laptop with a COM port, and have managed to get a software program called Termite (https://www.compuphase.com/software_termite.htm) running on it under Windows ME (using a straight thru cable).
Using Termite, we are able to receive data from the PLC with the COM port set up as: 9600 BAUD, 8 bits, 1 stop bit, No Parity. (We had to play with the BAUD rate, but the rest is the default Termite setup.)
A sample of the received Data Stream (on August 14, 2024 around noon):
"D240814101502 SOLAR ANGLE: -30.01<out of range> ARRAY ANGLE: -30"
Data appears about every 30 seconds. As you can see, the data immediately following the letter "D is the date and time set on the PLC: 24/08/14 10:15:02. (I don't know if the letter "D" is a 0D (carriage return) or just the letter "D" signifying that Date & time follows.)
The date is correct, however the time is about 2 hours slow.
As a result, I changed the battery (Panasonic ML-621S).
My QUESTION - How to get the PLC into a mode such that we can input the correct date and time ??
Questions that keep rolling around in our minds:
Do we terminate our response with a linefeed, a 'crlf, arrow key, ....??
Should the cable be "straight thru" ??
What about raising RTS/CTS ?
Should XON/XOF be set ??
Thanks,
Mike..