I am new to LabView and currently running with the 45 demo license.
I'm attempting to perform a Modbus RTU Master FC04 operation from my laptop to my target system via a USB-485 dongle. Currently I have a second USB-485 dongle attached to the RS-485 bus to allow me to monitor all bus communication (RTU sniffer)
in my example .vi file, I have my target system unit ID set to 32 (0x20) and I'm attempting a FC04 command reading from register address 0, requesting 64 (0x40) registers.
My sniffer port is recording this command from my LabView example code:
20 04 00 00 00 3F 3F 3F
but I expect it to send the following:
20 04 00 00 00 40 F7 4B
Can someone explain what I may be doing wrong here and why the '3F' bytes are being sent?
Thanks