Reading position data from GOT

[quoroy 0]

 

In this first picture is a numerical input with a monitor device D2058. In the whole GOT project this is the only device that saves the information inputed.

 

Then on que PLC sequence theres an instruction moving that device's value gotten from the GOT to the position module's buffer memory. My doubt comes when there's another device D10022Z9 getting the same value of D2058. In this case the Z9 index is always 0, I checked. In the whole PLC program this is the only part where the D10022Z9 appears, there is no instruction anywhere copying D2058 to D10022Z9 which is how I would think is the way it has the same data always. Am I missing something or how is this possible?

 

Edited 21 Mar 2016 by quoroy

[kaare_t 155]

Are you sure there aren't any BMOV instructions or loops that are copying data into D10022? In addition, how do you know that Z9 isn't being resetted or used elsewhere in the program? It could be that Z9 is SET to a value somewhere in the program, then RST elsewhere in the program. Remember that even if you monitor Z9, it can still mislead you to the belief that it's always 0. Most often, the value monitored is the value that are "longest" monitored within a scan cycle, hence if Z9 has a value in only 10 steps then you will still monitor a different value.

A way of testing this is simply to insert a MOVP instruction right before DMOV D2058.... with Z9 input and D* output. Then you can see which value are being used in Z9 at the moment the DMOV D2058... instruction is executed. Also look for loops and/or BMOV instructions. There may be that D2058 is being part of a "bigger" picture.

[quoroy 0]

That's a great idea, about adding the MOVP instruction to check, I did it and Z9 is always 0. I keep searching for any BMOV instructions or loops but I can't find any! it's like magic. I'll keep searching, thanks for your help!