Honeywell Experion Byte Swapping

[toddster900]

Hi All

I am currently trying to control a weigher over Profibus from an Experion DCS. I know there is byte swapping as I have successfully managed to test all of the control and status words. I used the mapping in the Profibus input and output blocks to carry out the byte swapping.

I am now trying to read the weight from the weigher but cant work out how to carry out the byte swapping on the double word value. Is there a library block that can carry out this byte swapping for me and if not could any one point me in the direction of how to achieve this?

Thanks in advance!

 

[toddster900]

This has raised its head again and I can not get any where with it. I am currently having to read the values into an S7 PLC on the same network, byte swap them in the then send them onto the DCS.

Any hint/guess at all would be good!

 

[Pete.S.]

This has raised its head again and I can not get any where with it. I am currently having to read the values into an S7 PLC on the same network, byte swap them in the then send them onto the DCS.

Any hint/guess at all would be good!

How do you connect to the profibus? Over a C200/C300?

You have Visual Basic in the C300 and also the ACE - if you have one of those in your network.

Byte swapping can be done several ways besides actually swapping the the bytes, for instance with division, multiplication and truncating. It can also be done with bit wise operations such as masking and shifting. Perhaps easiest is to read out the double word as 4 individual bytes and then mathematically assemble them together again in the right order. For instance 32bit word=byte1 + byte2*256 + (byte3 + byte4*256)*65536

 

[toddster900]

Thanks for the response. Access is through an SST profibus card on a C200 rack and no ACE unfortunately.

 

[toddster900]

Sorry on my phone and never saw your full response. That's fantastic. I'll try that next week!