Convert a Real to an Integer in S7-300

I am still looking but have not found the answer yet.

I am getting data from a Rice Lake controller thru Profibus DP
to a Siemens S7-314C-2DP PLC.

All of my data is in Floats. I want to convert some of it once it is in my PLC from Real to word.

All of the reals I need to convert are single didget numbers with nothing after the decimal place.

I need these values for data logs and I hate to give up space for a bunch of zeros.

AM hopping someone else has crossed this bridge and already has the answer.

Try RND to get double integer. And then there should be a truncate function to convert it to 16 bit integer. Or, you can use some address shifting to get the value you want in 16 bit format.

Say that you have your double integer variable in MD0 after converting to double integer. If you read MD2, you should be reading the value in 16 bit format.

However, you need to be sure that the value won't overflow 16 bit, otherwise... well, I guess you get the picture.

Make an FC (Let's call it FC1000 "Real2Int"
1. Declare "RealValue" as Real in the IN Table
2. Declare "IntValue" as INT in the OUT Table
3. Delcare "Temp1" as DINT in the TEMP Table
4. in FC1000 (I'm assuming your a ladder guy) Use ROUND function and Use "RealValue" in and "Temp1" Out
5. In the same network Move "Temp1" to "IntValue"

Now you can use FC1000 as many times as you like to convert Real to Int. A little verbose but easy for someone to follow.

Note I am assuming you checked that you are within range before you converted. Otherwise you could check in the block and report error etc.

Trunc & Move shud do ur job.
Gud Luk.

Nil