Split up / merge 2bytes to num or hex

RAPID Programming
1

Hello everyone,

i’m receiving 2 bytes from a plc and wonder if there’s a way to merge them. I thought about ‘convert’ them to hexadecimal or just add the binary data together..
for example .. incoming values byte 1: 76, byte 2: 162 – desired result: num: 19618

0x4C & 0xA2 → 0x4CA2
or 01001100 & 10100010 → 0100110010100010
and then convert it to decimal..

2

Is this via a group input? If so, why not make one, sixteen bit group?

3

yes, but for tests i’m working with a virtual irc5 and think i only can use

https://robotapps.robotstudio.com/#/viewApp/2cab7b4f-754c-415b-a32c-cbe4da9353e9
``
(RSConnectGIOToSnap7)

which only provides singles bytes..
For real profinet connection lateron, i already set up 16bit groups.. but for now this wont work i think.
Correct me if i’m wrong

4

Ok i’ve found the correct syntax (ByteToStr(byte\Hex)).. was’nt as hard as i expected

    FUNC num mergedX(byte x0,byte x1)
        VAR bool b_temp;
        Xkoord:=hexToDec(ByteToStr(x0\Hex)+ByteToStr(x1\Hex));
        b_temp:=StrToVal(Xkoord,mergedbytes);
        RETURN mergedbytes;
    ENDFUNC

Improvements?

5

Hello,
You can define a group encompass your bytes.
Like:


      -Name "giFirstByte" -SignalType "GI" -Device "MyPNDevice" -DeviceMap "0-7"
      -Name "giSecondetByte" -SignalType "GI" -Device "MyPNDevice" -DeviceMap "8-15"

      -Name "giMyWord" -SignalType "GI" -Device "MyPNDevice" -DeviceMap "0-15"
6

Hello,

you can calculate the value as follows:

TPWrite "Value: "\num:=CalcValue(76,162);

FUNC num CalcValue(byte byte1,byte byte2)
    RETURN byte1*256+byte2;
ENDFUNC

BR
Micky

7

Ok this looks better.. but when i do so, the result is byte-swapped..
i tried to map the word vice versa but then it comes to a nonsense result.
Bytes swapped:

image.jpg
image.jpg576×141 62.5 KB

… dont know:

image.jpg
image.jpg579×143 67.9 KB

8

Thanks Micky, this works as expected.
Denis, can you tell me what i’ve mapped wrong?

Best Greetings.

9

What if you map first byte to second and vice versa? Leave word as is. Or inverse map first and second byte, also leave word as is.

10

yes that’s propably the simplest way.. too easy to think about it :smiley: 2nd idea wont work but mapping first to second byte is doing the job.

Thank you all :slight_smile:

11

Hello Papa,

why don’t you combine the two bytes to a group input (16 bit), then you save yourself the later conversion
You can define the signal mapping for the group inputs as follows:
“16-23,24-31”
You can also use here the bit or byte swap, e.g. “23-16,31-24”

best regards
Micky

12

Thx Mickey, thats the way i’m doing it right now.
First Byte mapped from 24-31, second Byte from 16-23 (to avoid byte swapping), Word mapped 16-31 and everything works fine