How to make a 4 state and 2 bit decision faster.

I fully agree with Nemo, this logic would work best in the PLC.

However ... if you have to do it in WinCC then there are a few things that may help.

1. If your tags are boolean tags then you can use a Dynamic Dialog with an expression like
'tag1' + ( 'tag2' * 2 ). You can then use an Analog return type and enter four ranges from 0 - 3

2. If you are bit-picking an analog tag then you could try modifying your script to use a case statement instead. I cannot guarantee that this will improve the performance but it may help. I have modified your example below.

[code]
BOOL aux1=GetTagBit("tag1");
BOOL aux2=GetTagBit("tag2");
int total;

total = aux1 + (aux2 * 2);
switch(total)
{
case 0 :
return 0;
break;
case 1 :
return 1;
break;
case 2 :
return 2;
break;
case 3 :
return 3;
break;
}
[/code]