Label - Expression to conditionally format Hex value

Ignition
2

This expression will do the trick:

stringFormat('%02X:%02X',
    ({KasaTMMC/Final4/F4-TL/P1_S001A} >> 8), 
    ({KasaTMMC/Final4/F4-TL/P1_S001A} & 255)
)

An explanation of how this works.

  1. The stringFormat expression accepts format strings which utilizes the Java String Format Syntax, found here. Esentially, this string is saying it will take 2 arguments and format them both as a Hexadecimal Integer with zero padding to a width of 2 characters.

  2. This: {tag} >> 8 performs a right bit shift to the value of tag 8 bits to the right. It helps to think of the numbers in binary. In this instance the binary value would be 0b0000 0111 0000 0111, following the bit shift the resultant value is 0b0000 0000 0000 0111.

  3. This: {tag} & 255 performs a bitwise AND operation between the value of tag and 255. Again it helps to think of the numbers in binary. In this instance:
    0b0000 0111 0000 0111 & 0b0000 0000 1111 1111 = 0b0000 0000 0000 0111

The resultant string will be 07:07

4 Likes