Looking to insert a hexadecimal value into an array in order to write to a device via modbus/TCP using socket communication.
Currently facing an issue where I am unable to retrieve the hex value with the same data type as the elements present in byteArrayWriteTemperature.
After calculating the crc for preparing the array to be sent, it is necessary to add this crc at the end of the array.
For instance, if value = 45, my resulting array would look like:
array = [0x01, 0x10, 0x04, 0x00, 0x00, 0x01, 0x02, 0x00, 0x2d, 0x23, 0x8d]
When using the Crc16() method on
buff = [0x01, 0x10, 0x04, 0x00, 0x00, 0x01, 0x02, 0x00, 0x2d]0x2d (equivalent to decimal value `45`), the generated crc result is swapped = 8d23 rather than 238d as seen in the last 2 elements of array.
setTemperature(value: number) {
console.log('about to set temperature value ', value);
let hex = value.toString(16)
const byteArrayWriteTemperature = [0x01, 0x10, 0x04, 0x00, 0x00, 0x01, 0x02, 0x00, hex];
let crc = this.Crc16(byteArrayWriteTemperature, byteArrayWriteTemperature.length)
console.log('crc ', crc)
console.log('array: ', byteArrayWriteTemperature);
this.writeToDevice(byteArrayWriteTemperature)
}
Crc16(buff, length) {
let crc = 0xffff;
for (let pos = 0; pos < length; pos++) {
crc ^= buff[pos]; // (uint8_t) // XOR byte into least sig. byte of crc
for (let i = 8; i != 0; i--) {
// Loop over each bit
if ((crc & 0x0001) != 0) {
// If the LSB is set
crc >>= 1; // Shift right and XOR 0xA001
crc ^= 0xa001;
} else {
crc >>= 1; // Just shift right
} // Else LSB is not set
}
}
return crc;
}
Seeking guidance on how to properly format my array. Thank you