Steve Bailey
Lifetime Supporting Member + Moderator
I looked at some of the other datasheets for different models from the same manufacturer. I didn't see any menu selection to enable/disable Modbus. There is a password entry, but generally on devices like this, the password is only used to restrict access to parameter changes.
Other models from the same manufacturer allow you to select the number of stop bits and data bits, so I like Bernie's suggestion to try different settings in the software on your PC.
If your USB/serial converter has LEDs that indicate traffic, check to see if the LED for the Rx line ever blinks. Based on your settings in the screenshot you should see the LED for the Tx line blink every three seconds. If that [00] character is coming from the Modbus slave, you should also see the Rx LED blink shortly after the Tx LED.
Also, have you checked Windows Device Manager to verify that the USB/serial converter is COM3?
Other models from the same manufacturer allow you to select the number of stop bits and data bits, so I like Bernie's suggestion to try different settings in the software on your PC.
If your USB/serial converter has LEDs that indicate traffic, check to see if the LED for the Rx line ever blinks. Based on your settings in the screenshot you should see the LED for the Tx line blink every three seconds. If that [00] character is coming from the Modbus slave, you should also see the Rx LED blink shortly after the Tx LED.
Also, have you checked Windows Device Manager to verify that the USB/serial converter is COM3?