Byte to Word

[Akshay Ganeshkar 0]

I am having problem working with Mitsubishi FX5 PLC.

How to send two bytes data into one word.

I want to send first byte into lower word and second byte into upper word.

[panic mode 246]

the same way you would do that with digits in a decimal system. if you want 3 and 8 to become 38, you multiply first one by ten then add the second one.

in case of 8-bit, you multiply first one by 256 or simply shift it left 8 places then add or OR result with the second byte.

 

[AndreasW 21]

instead of shifting the bits you can use the swap instruction

1.) MOV HighByteValue  D1                 // move the High-Byte to D1 (this will be stored in the lower 8 Bit of D1)
2.) SWAP D1                                        // swap Hi/Lo of D1 (High-Byte-Value will stored in the upper 8 Bit of D1)
3.) WOR LowByteValue D1                  // OR the value of the Low-Byte of D1 

 

 

[panic mode 246]

yup, that will work too.  as usual there are many ways to get the same result.

on a side note - without knowing where the data comes from and what the result is used for, i would just suggest some caution with data manipulation. you may want to check or ensure that "byte values are indeed only 8 bits or you may get surprise result. 

if the byte values are from some bitwise memory like I/O or M, you can use form that only takes 8 bits (for example K2M100). if the byte values are stored in D registers you may want to clear higher bits..

 

for example

WAND HFF  HighByteValue HighByteValue  

WAND HFF  LowByteValue LowByteValue