Cape comms2のModbus RTU RS485をBeaglebone blackで動作させるには？

私はCape comms2を設定し、Debianを実行しながらModbus RTU RS 485をBeaglebone Blackで動作させようとして数日間頭を握りました。

/dev/ttyS0私は次のように9600ボード、8ビットデータ、1ビットストップ、パリティなしでNodeJSソフトウェアに接続します。

            let SerialPort = require("serialport");
            let serialport = new SerialPort(this.device, { autoOpen: false, baudRate: 9600, stopbits: 1, databits: 8, parity: 'none' }, false);

            this.log('Opening serial connection… (client = ModbusRTU())')
            const client = new ModbusRTU(serialport)
            this.success('client is', client)
            this.log("Port Open Status: " + client.isOpen);
            client.open()

            // set a timout for requests default is null (no timeout)
            client.setTimeout(2e3)

            setInterval(() => {
                this.log("Port Open Status: " + client.isOpen);
                if (!client.isOpen) return

                run()

            },10e3)

            var i=0
            const run = () => {
                this.success(`Connected!`)

                this.success('--> Running…')
                if (i&1) read()
                else write()

                i++
                
                this.log('<-- Leaving run, but wait for the response in the future call back…')
            }

            /**
             * Read the RS485 packet: start adress 0x0C count 1 register
             */
            const read = () => {
                // read the 2 registers starting at address 5
                // on device number 1.
                this.log('About to read, setting the ID to 0xD2…')
                client.setID(0xD2)
                this.log('Now reading 1 register from start address 0x2A, wait for the response…')
                client
                //.readHoldingRegisters()
                .readHoldingRegisters(0x2A, 1)
                .then(args => this.log('Received SoC:', ...args))
                .catch(err => this.error('Received eror:', err))
                .finally(() => this.log('Received: finally'))

            }


            /**
             * Write to the RS485 register
             */
            const write = () => {
                // write the values 0, 0xffff to registers starting at address 5
                // on device number 1.
                //this.log('Writing: 0xD2, [0x03, 0x00, 0x0C, 0x00, 0x01, 0x57, 0xAA,]')
                this.log('Writing: FC3 0xD2,0x2A,1')
                client.setID(0xD2)
                if (true) {
                    client
                    .writeFC3(0x06,0x2A, 1, (err, data) => {
                        if (err) {
                            this.error('writeFC3:', err)
                        } else {
                            this.success('writeFC3:', data)
                        }
                    })
                }
            }

私が得たログは次のとおりです。

Pepsr v2.2.236 9:56:14 AM