RSLogix - DEC value to HEX string

JohanM · May 4, 2016

Hi guys.

Sorry if I am asking for something solved, but I cant find any useful and easy information for me. I am looking for some solution how to convert decimal value in byte to hexadecimal representation in string in RSLogix..

I need it for FactoryTalk visualization, because I am not able to find how to show decimal value as hex... Do yo know some sample? or something?.. A lot of thanks..

bernie_carlton · May 4, 2016

Since you didn't specify which RSLogix I'll answer in a general form.

Extract each of the two 4 bit nibbles from the byte into the low bits its own byte.

For each byte add 48 (30 hex) to the value
If the result is greater than 57 (39 hex) then add 7 more to the value
The result is the ASCII representation (0-9 A-F) of each nibble.

AustralIan · May 4, 2016

Code:

myUSINT = 5AH;

String.LEN := 2;
tempUSINT := ((myUSINT & F0H) / 8);
IF tempUSINT > 9 THEN
  String.Data[0] := tempUSINT + 55;
ELSE
  String.Data[0] := tempUSINT + 48;
End_IF;
tempUSINT := (myUSINT & 0FH);
IF tempUSINT > 9 THEN
  String.Data[1] := tempUSINT + 55;
ELSE
  String.Data[1] := tempUSINT + 48;
End_IF;

votecoffee · Feb 24, 2020

Dynamically sized AOI

I made an AOI based on AustralIan's code
AOI export is attached.

Create a SINT array sized to fit (if you want to create a generic array and specify lenght, you need to modify the AOI)
Copy data to SINT array (remember COP length is destination element size, so a DINT to SINT copy is x4 the length of the DINT array)

COP HMI_PLCVersion_LINT HMI_PLCVersion_SINT[0] 8 DTOS_Hex DTOS_Hex HMI_PLCVersion_SINT HMI_PLCVersion

Parameters:

Code:

Byte    InOut    SINT[1]
HexString    InOut    STRING

Structured Text Logic:

Code:

//Determine the size of the passed in array
size(Byte,0,Byte_Size);

HexString.LEN := Byte_Size*2;
for i := 0 to (Byte_Size - 1) do
    TempDINT := ((Byte[i] & 16#F0) / 8);
    IF TempDINT > 9 THEN
      HexString.DATA[i*2] := TempDINT + 55;
    ELSE
      HexString.DATA[i*2] := TempDINT + 48;
    End_IF;
    TempDINT := (Byte[i] & 16#0F);
    IF TempDINT > 9 THEN
      HexString.DATA[i*2 + 1] := TempDINT + 55;
    ELSE
      HexString.DATA[i*2 + 1] := TempDINT + 48;
    End_IF;
end_for;

Webhead · Jul 15, 2020

I'm attempting to use your AOI but I'm sure I'm doing something wrong. I'm new to RSLogix and have not learned the verbiage just yet. I'm getting error messages and I know I have to fill the functions with something but not sure what.

Geoff White · Jul 15, 2020

You need to create and instance of the AIO to use in the AOI calls.
Stick a tag name in the DTOS_Hex field and create a tag of the type DTOS_Hex.
You can use the same instance for both calls because they have no state.

RSLogix - DEC value to HEX string

JohanM

Member

bernie_carlton

Lifetime Supporting Member + Moderator

AustralIan

Member

votecoffee

Member

Webhead

Member

Geoff White

Member

Similar Topics