john paley
Member
Programmers of all type PLC's:
We are presently wrapping up a project to replace DC drives on a paper/plastic web handling machine.This project also included wholesale replacement of an old surface winder with a brand new dual turret center winder--manufactured in Europe.
The machine drives are rockwell--reliance webpack 3000's, controlled via controlnet by an AB controllogix processsor.
The winder drives are siemens--controlled via profibus by an s7 PLC.
We use a third party (SST) card in the controllogix rack to talk to the siemens S7 over the profibus. The data is exchanged via tarnsfer of a gazillion integers.
When we started up the SST card, we found the bytes of the siemens integers to be transposed--that is the lsb was bits 8-15 and the msb was bits 0-7---just the opposite of what controllogix was accustomed to. The siemens guy was able to reverse the bytes and everythin is OK but now for the million dollar question and that can of worms. Who the heck is backwards, AB or Siemens??
My two cents--I think it's siemens who's backwards, not just because I'm an AB fan, but because siemens had hooks available in their system to easily reverse the bytes--like they knew it would need to be done, at some time--the programmer did it in about a half an hour.
We are presently wrapping up a project to replace DC drives on a paper/plastic web handling machine.This project also included wholesale replacement of an old surface winder with a brand new dual turret center winder--manufactured in Europe.
The machine drives are rockwell--reliance webpack 3000's, controlled via controlnet by an AB controllogix processsor.
The winder drives are siemens--controlled via profibus by an s7 PLC.
We use a third party (SST) card in the controllogix rack to talk to the siemens S7 over the profibus. The data is exchanged via tarnsfer of a gazillion integers.
When we started up the SST card, we found the bytes of the siemens integers to be transposed--that is the lsb was bits 8-15 and the msb was bits 0-7---just the opposite of what controllogix was accustomed to. The siemens guy was able to reverse the bytes and everythin is OK but now for the million dollar question and that can of worms. Who the heck is backwards, AB or Siemens??
My two cents--I think it's siemens who's backwards, not just because I'm an AB fan, but because siemens had hooks available in their system to easily reverse the bytes--like they knew it would need to be done, at some time--the programmer did it in about a half an hour.