Using MyRio's UART Pins to Control an ESP32-Based Driver Board

[jiawenhsieh]

I am trying to use LabVIEW's VISA Write to send commands from MyRio to the Waveshare Bus Servo Driver HAT (A) to control their RSBL 45-24 servo motors. Based on the sample code provided on the official website, I have identified the command format required for transmission, but I am unsure how to correctly send and receive the data.

Currently, I have connected MyRio's Rx/Tx pins to the driver board's Rx/Tx pins designated for Raspberry Pi. I then input the following hexadecimal string into VISA Write:
FFFF 0107 031E 0002 CE
(start bytes, ID, data length, instruction, data, checksum) to make motor ID 1 rotate to 45 degrees. However, the motor does not respond, and the Error Out shows:
status: correct, code: 1073676294.

I am a beginner and might have misunderstood many things. I would appreciate your help.

RSBL 45-24 (https://www.waveshare.net/shop/RSBL45-24.htm)
Bus Servo Driver HAT (A)(https://www.waveshare.net/shop/Bus-Servo-Driver-HAT-A.htm)

[altenbach]

We cannot debug images, please attach your VI.

Your program seems incomplete..

• A baud rate is an integer, not orange and never 1E+6.
• Your boolean switch is FALSE, so the true case shown does not even execute.
• Bytes at port is often wrong, isn't there a termination character (start here)?
• Do you have a link to the manual of the device?
• Do you know LabVIEW basics?
• etc.

[Bob_Schor]

The Waveshare Wiki has a lot of information about these products, including a link to control things using Python.  There doesn't seem to be LabVIEW drivers there, but you might send them a description of what you are trying to do and see if, for example, you can "reverse-engineer" their Python example to work with LabVIEW.  To do this, you probably need to know more about their communication protocol, and then learn enough LabVIEW to set up VISA communication.

If you are just getting started in learning LabVIEW, even if they have a LabVIEW driver, expect to spend several weeks getting this working.  Having a LabVIEW "mentor" (or "guru") around would be very helpful.

Bob Schor