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I have two Modbus systems (scada-master and slave-logger) connected via radio. I have the ability to use two types of radio-modem with RS232 port. One works at 2.4GHz and the other at 868MHz.
With the first couple of radio couple 2.4GHz everything works. I use Chipkin to simulate the scada, request are sent for registers 16 (40001 up to 40016) and the slave responds fine.
With the couple of radio-modem 868 MHz, the request arrives at the remote slave (I can see the RX LED that lights) but the logger slave does not respond. So I want to see if the couple of 868 MHz change the string that reaches the remote slave.
Please anyone can suggest a SW that can occur if the request comes changed? Like a SW that sniffer and converts the string.
To do this I have set up another PC with the serial port with only GND and RX wire. For each scada request, I can see coming strings that look the same, whether the radio is at 2.4GHz, both in the 868MHz. It is possible to parse strings to see if they are different. Of course I make these test in a room, in the laboratory. The different frequency and short distance do not make difference and problems. Also because with other sw and other protocol all systems works,with both types of radio!
Many thanks in advance and sorry for my English.
Regards
Sandro
With the first couple of radio couple 2.4GHz everything works. I use Chipkin to simulate the scada, request are sent for registers 16 (40001 up to 40016) and the slave responds fine.
With the couple of radio-modem 868 MHz, the request arrives at the remote slave (I can see the RX LED that lights) but the logger slave does not respond. So I want to see if the couple of 868 MHz change the string that reaches the remote slave.
Please anyone can suggest a SW that can occur if the request comes changed? Like a SW that sniffer and converts the string.
To do this I have set up another PC with the serial port with only GND and RX wire. For each scada request, I can see coming strings that look the same, whether the radio is at 2.4GHz, both in the 868MHz. It is possible to parse strings to see if they are different. Of course I make these test in a room, in the laboratory. The different frequency and short distance do not make difference and problems. Also because with other sw and other protocol all systems works,with both types of radio!
Many thanks in advance and sorry for my English.
Regards
Sandro