I've done some conversions (but not PLC-2 to SLC). But I can offer you these tips:
If at all possible, before you convert, assign PLC addresses that will correspond to the PLC-2 address. An easy scheme would be:
N10:0-99 = 000 - 099, N11:0-99 = 100-199, etc.
Assign symbol names to each register. Since you can't start a symbol with a number, use something like X### for words and X##### for bits. When you enter you code, use the symbol name, rather than the 'real' address
When you come to timers and countes, remember that the single address shown is for the ACC word. The DN, EN, etc bits are part of that word. The .PRE is 100 words up from that address. Since you will have to use a T4 address with a timer, instead of N10 address, change the symbol X### to be the T4 addresses of the .PRE, .ACC, and .DN. This way, when you run across them in your program, since you enter them by symbol, they go to the correct addresses automatically.
You can view the code using symbols instead of addresses, and it should look almost the same as your PLC-2 code. This helpsy you debug the code by visual inspection, which helps eliminate typos introduced in the conversion process.
Read the Programming and Operations manual very carefully, and understand what each function does. Don't worry about having a single instruction that's equivalent - if you understand what it does, you can write a block of code that does the same.
When converting from a GE Series Six to a SLC, for example, the SUB instruction is often used as a Greater than or Equal to function as well. I didn't try analyzing each case to see if it was being used that way, I just kept the SUB, and branched around with a GEQ.
After the code is in and functional, then you can clean it up.
Beleive me, it will look ugly.
Good luck
