I'm trying to reverse engineer a client's program. They are sending Logic Command and Speed Reference over DeviceNet to a PowerFlex 40P VFD.
The output is a DINT. The first word (0-15 bits) are the logic command. The next word (16-31) are the speed reference.
However the vendor who wrote the program decided to use a COP to copy their UDT of 16 bools and an INT directly into the Output DINT. I don't quote understand how Logix knows what bit is part of what word.
Here are some screenshots. The UDT is equivalent in size to a DINT, but I can't seem to figure out which part of the UDT corresponds to what bit when copied. Notice the INT is smack dab in the middle of the structure. Also the bits don't seem to match up (whether I go from MSB or LSB) per the PowerFlex documentation.
PS: It's in Italian
The output is a DINT. The first word (0-15 bits) are the logic command. The next word (16-31) are the speed reference.
However the vendor who wrote the program decided to use a COP to copy their UDT of 16 bools and an INT directly into the Output DINT. I don't quote understand how Logix knows what bit is part of what word.
Here are some screenshots. The UDT is equivalent in size to a DINT, but I can't seem to figure out which part of the UDT corresponds to what bit when copied. Notice the INT is smack dab in the middle of the structure. Also the bits don't seem to match up (whether I go from MSB or LSB) per the PowerFlex documentation.
PS: It's in Italian
