RS 500 ML 1400: Combine 2 consecutive Int Words in to a Long

I am getting data from a modbus device and I need to combine 2 16 bit N registers in to 1 32bit L register.


I have tried a CPW
N242:2 -> L245:0 Length of 2
I get 292,552,705 when I should get 70,000


N242:3 is the lower register, N242:2 is the higher register.


Edit:


ooooooh see Screen shot of Help file for CPW.

I assume so I assume a ML1400 is Little Endian, but the device is Big Endian.



Ok so can I handle this without creating a 3rd register location to be a temp register for swamping the words?

70,000 base 10 = 0x0001,1170 (base 16 i.e. hexadecimal)



292,552,705 base 10 = 0x1170,0001



N.B. Commas at powers of 1000 base 10 and 0x10000 base 16.


I trust you can take it from there?

Is a ML1400 big endian or little endian?



the 16bit word endianness seems to match the device but the 2 words are swapped


So either Rockwell is screwy or IFM is screwy.

The CPW is right for a ML1400. It is a bit for bit copy. The Length for CPW is the number of 16 bit "words" to copy. This is different than the COP which bases the length on the number of destination elements which can vary. The COP doesn't support some types of data with different element sizes in the Micrologix.

You might have to shuffle the words around prior to the CPW. I don't spend a whole lot of time trying to read the manuals and interpret word order when I can run a trial and if I get gibberish, swap the words...if I still get junk, swap the bytes...rarely you have to do both.

OkiePC said:

I don't spend a whole lot of time trying to read the manuals and interpret word order when I can run a trial and if I get gibberish, swap the words...if I still get junk, swap the bytes...rarely you have to do both.

Click to expand...

Exactly, the number of times I have first figured out what works, before figuring out why it works is maddening, but that's the job.


Try this before the CPW:


XOR N242:2 N242:3 N242:2
XOR N242:2 N242:3 N242:3
XOR N242:2 N242:3 N242:2

I got it working

I just did 2 movess and dropped them in a temporary resister. Then did my CPW. I might work improving it later, right now I have to get this done LOL.