Guidance for newbie - RSLogix 500 (AB)

[ckchew666]

Hi,

Appreciate if any of the guru's here can explain what is happening with the addressing as per attachment, B83:51 and at the NEQ instruction in attachment 2.

Thanks in advance.

 

[ckchew666]

Attachment 2

 

[(8{)} ( .)]

Hi ckchew666

This is called indirect addressing.

The instruction is comparing the value of a word in B83 to 0. The word being compared depends on the value of the counter accumulator.

For instance if C85:0.ACC = 5 then the NEQ instruction will be true when B83:5 <> 0. When C85:0.ACC = 20 the NEQ instruction will be true when B83:20 <> 0.

B83:51/[N90:100] works the same way except that in this case the value of N90:100 determines the bit that is examined in word B83:51.

For example if N90:100 = 6 then the XIC (NO) contact will be true when B83:51/6 = 1.

Hope this helps.

Good Luck,

(8{)} ( .)

(Yosi)