Comm Operator is a professional tool for RS232 serial port and network communication. It’s your good helper to design, development, debug and test applications and hardware devices.
Here we list an application sample about how to control Velleman K8090 /VM8090 USB relay card with Comm Operator.
Connect Velleman K8090/VM8090 USB relay card with your computer.
Run Comm Operator.
Open Com Port connected with Velleman K8090/VM8090 USB relay card, and select Baud Rate 19200.
Click menu Tools->Option->Checksum to select checksum method “0x100 – (Z1+Z2+Z3+…+Zn)” .
Click menu View –> Structured Data to show Quick Send – Structured Data panel.
Click Edit button to add New data items for STX, CMD, MASK, PARAM1, PARAM2 and ETX; add New Var for checksum according to the Velleman K8090/VM 8090 protocol manual.
“Packets for the K8090 are 7 bytes in size. Each packet is delimited by the STX (04h) and ETX
(0Fh) bytes. Validity of the packet can be checked by verifying the checksum byte (CHK).”
“The K8090 uses the two’s complement for its checksum. This means adding all bytes up to and
including param2, negating the result and adding 1. “
-(STX + CMD + MASK + PARAM1 + PARAM2) + 1
Here is the added structured data.
Click Send button to send data packet to Velleman K8090 USB relay card.
The sample packet is to switch all 8 relays on.
Edit data items according to the Velleman K8090/VM8090 protocol manual, it’s easy to control the relay card.
Here is the video about how to control Velleman K8090 USB relay card with Comm Operator.