Hi,

I have done some searching and reading, but still could not find an explanation to the following issue. I am adding a new HMI (WW Intouch) to an older Modicon Quantum PLC. I have no experience with ladder logic. I am trying to figure out how to create a 3 position selector with a single feedback indication. Lets take a HOA switch for example. I would like to add a field next to the switch that would have text, indicating either HAND or OFF or AUTO, but only one at a time. One of the ways to do it in HMI is to make only 1 of 3 visible at one time, based on an input state, but I'm wondering if previously used HMI had different bits setup based on ladder logic block. I sketched what I currently have in the ladder:

https://picasaweb.google.com/115155...2015?authkey=Gv1sRgCKeInPWn5NmD0AE&feat=email

As you can see, instead of sketching 3 identical rungs, I just stacked references. My questions is - what do the 3 MBIT blocks do? I believe, previous HMI used reference 400351 for status indication, instead of 3 separate reference, but I cannot understand/figure out where is the bit, defining the current position of the switch.

 

It's a Veeerry long time since I last used a Modicon but I'm guessing the logic is turning on Bit #2, 3 or 4 of word 400351.

In the graphic there is likely a script making the text visible depending on the bit state.

I don't understand why the 2 coils seem to have 3 addresses eg 000401,000402,000403b but you probably understand modern Modsoft better than I.