Yep - thanks for all the hints and help.
Hopefully 1 last questions - you are calculating the CRCs and reporting whether they are accurate/correct - do you just run through a bunch of different CRC algorithms at the start of a capture to try and work out which is the correct one ?
I need to have my system generate packets and was wondering is there somewhere that you identify which algo you settle on for the checksum decode ?
Perfect thanks !!! Now i am getting a good decode of what is going on
Is there anyway to export the Hex Strings (without decode) into a text file
I often find it easier when decoding unknown devices (in terms of registers) to look for patterns and things that are constantly changing to give a hint as to what the data could represent.
Your decode window etc is brilliant i must say though !!
Hey Vladimir, Thanks for the quick response - yes i have gone for the diagram on the left when connecting as i assumed i would want to be a man in the middle rather than thinking about how RS485 works and just tapping into the interface as you have shown.
I assume as i am just listening i would tap into the RX+/RX- lines - whereas if i wanted to inject i would tap into the TX+/TX- instead ?
I have a new Serial Tap i have purchased.
The purpose for this was to snoop on comms between my Goodwe AC Battery inverter - SBP5000 and the energy meter i comes supplied with the GM1000D.
I have a 3 phase house and these energy meters are single phase only - as are the batteries/inverters - so i have one connected to each phase of my house.
My plan is to have a raspberry pi talk to the 3 energy meters, request the data and then fool the Inverters into thinking they are talking to the meter by sendng back altered information that will ensure i end up with batteries that are evenly servicing the loads to ensure our grid import/export is Net Zero.
I have therefore disconnected one of the inverters from the Meter, connected it to the Serial tap - RS485 port and then created a new short lead to go from the RS485 on the Serial Tap to the Meter.
I was therefore expecting to see a continual stream of information - requests every 200ms from the inverter and then responses from the Meters.
The link speed and settings are well documented by Goodwe as 9600,N,8,1 which is what i have set in IO Ninja (V5) but i am getting continual framing errors.
If i disconnect the Serial Tap and instead put the inverter back to the meter they start communicating straight away.
Any pointers on this ?