Help on MW,MD,

Hello friends

Plz explain that MW and MD for me because I am using it and don,t know the full function of it.I use it in scaling PT100.
I call FC105 input 336 and high limit 100 low limit 0 bopiler 0
RET_VAL I put MW6 and out MD10.Now MD10 showing the temperature as it is but I confuse what is that MW and MD and how to compare it for high or low limit stop.

Thanks
Usman

Hello Usman.

"W" is for a word-sized address, i.e. 16 bits. That can again be a WORD or an INT (as the input to FC105).
"D" is for a double-word-sized address, i.e 32 bits. That can be a DWORD, a DINT, a REAL (as the output of the FC105) or a TIME variable.

Euhm do you need FC105 for a PT100.
Like i know it PT100 is an integer value that is been readed by RTD card and divided by 10 gives you the Real value.
Maybe i'm wrong, but then ignore this.

Thanks you both for your kind response because i was really confused about that I was think before that maybe that is values for analog inputs and outputs.Anyway thanks again
Usman

BOOL, eg M 6.0, uses 1 bit in MB6

BYTE, eg MB6 uses all 8 bits in MB6

WORD, eg MW6 uses MB6 and MB7, all 8 bits in both bytes.

DOUBLE WORD, eg MD6 uses MB6, MB7, MB8 and MB9, all 8 bits in all 4 bytes.


A common error for a newby is to use addresses that are crossed, eg use MW6 and then later on a BOOL in MB7 etc..