I'm trying to connect my Victron Energy Smart Solar MPPT 75/15 to an Arduino UNO Wifi Rev2 via the VEDirect to USB cable. The 75/15 is configured for normal Tx, so as I understand it, it SHOULD be transmitting character data every second.
The Arduino sees nothing. So, I'm inclined to suspect one of the following:
1). The VEDirect to USB cable is opto-coupled, rather than inductively coupled; and the USB side of the connector requires 5v power, which the Arduino does not supply.
2). The Smart Solar does not transmit character data via VEDirect when it is operating in bluetooth networking mode.
3). The Tx and Rx pins are reversed.
Can anyone confirm any of these possibilities, or suggest a solution? I'm tempted to direct-wire the two devices, but I'd prefer to avoid that if possible.
Do I understand that correctly, you connect that device to the USB connector of the Arduino UNO WiFi? That board is only a USB slave, it isn't capable of changing to the USB master role.
Providing power to the USB interface is the smallest of your problems.
Unfortunately I didn't found a description of what VEDirect is or how it may interact with a MCU. Post links to that information if you want us to help further.
Thank you very much for responding. I was hoping to get the attention of someone who has actually connected an Arduino to a Victron Energy product via VE.Direct.
At this point, I'd like to keep the scope of the problem simple: Why am I not seeing any activity on the Rx pin of the Arduino USB? Victron has excellent documentation on their communication protocol at Technical information - Victron Energy. The applicable documents are "Data Communication with Victron Energy Products", and "VE.Direct Protocol". In a nutshell, their device sends a burst of character data every second, without any form of handshake.
I've ordered another cable from Victron - this time a simple point-to-point cable. Once I have it, I'll be able to use a logic probe to determine if the Victron device is transmitting, and on which pin. The real question remaining will be "Is my VE.Direct to USB cable defective, or is it failing because the Arduino is not supplying 5 volts?" Victron does not provide any information about their VE.Direct to USB cable, other than stating that it is "galvanically isolated."
I just received an answer on the Victron forum: The VE.Direct to USB cable contains opto-isolators and will not function unless power is supplied from both ends. They state that direct cabling works, with no issues like signal over-voltage.