Omron FINS Driver String Byte Order

[bill.liu]

I am using an Omron NX CPU. The pair of characters in each 16 bit word are swapped when the String type is used in the OPC path - "ABCD" becomes "BADC". I tried all the Data Type Modifiers (@BE, @LE, @HL, @LH) but they don't have any effect. Is this behaviour expected?

As a workaround, I am using a derived tag to swap the byte order on reading and writing but ideally I wish the Omron FINS driver can handle this. In comparison, Kepware supports HiLo byte order, LoHi byte order,Only High byte and Only Low byte for their String data type.

[David_Stone]

String Format byte order

Just so you don’t scratch your head for too long on this: s = "eRicep1 32" s = ''.join(c for pair in zip(s[1::2], s[::2]) for c in pair) s[1::2] and s[::2] will produce strings with even or odd characters ([1::2] = start from 1, stop at the end, step 2), zip will take one character from each, then it’s simply a matter of putting things in the right order. So, with "eRicep1 32", s[1::2] will be "Rcp 2" and s[::2] "eie13" zip("Rcp 2", "eie13") produces the pairs [('R', 'e'), ('c', 'i'), ('p'…

Related Thread.

[Kevin.Herron]

The byte/word order modifies do not currently apply to String values - you'll have to look at workarounds like the one @David_Stone suggested.