HMI Question/Doubt

[Andrei Blagaila 4]

I attache two photos to go with my problem. I'm using GXWorks2 and GT Designer 3. The project was written by someone else. I want to make a couple of improvements. As you can see from the ladder diagram there is a manually written SET and RESET command for L600 and B1700. You see the settings done in Designer in the second picture. It was on Momentary, I switched it to alternate and deleted the area marked in red on the ladder diagram. Can someone confirm that it will work the same way? Or can someone explaine why they did it like this? I like clean SW if possible. Do I lose the latch if I power off and need to reset it like this? I can't think of another reason for doing it like that.

Thank you

[kaare_t 155]

Your solution will not work as expected at all (if my head works correct right now)

1. You've removed the prerequisite M301 in the first line - are you sure that this isn't needed?
2. M5200 is pulsed and not using SET/RST. Hence L600 and B1700 is pulsed in this rung, and is never SET or RST. In other words when you select alternate it will be constant either ON or OFF and not like a trigger as in the picture above.

As a general note: Why don't you create a test project (just a fresh project without anything in it) in the SW. Then, you can write test code there and run the simulator to test it. That way you can actually see what's going on in the code.

E.g. For your example above you can first write the complete code, and simulate the HMI with pulse functions for the "Momentary" (e.g. PLS X1700) and use SET/RST for alternate functions in the code. The only thing needed for your example would be to implement a rung first that is either using PLS (momentary) or SET/RST (alternate).

By using this approach you can actually see what's going on, what you can do to enhance your code and what will not work as expected.

[Andrei Blagaila 4]

Thank you for your answer. I already did that. M301 was forgotten but for a test I did not need all the details. So when i pun alternate it switches on L600 and keeps them on. The original diagram did the same but instead of using alternate it used a pulse but once the pulse activated L600 turned on and stayed on until another pulse.

My question (badly phrased I realize) was in the two diagrams is there any change in L600. When I turn off the PLC or HMI do I lose this setting? I use L relays to activate certain functions of the machine (machine is customizable). It does the same for every option as shown in the pictured in the first post. I wanted to simplify the software a bit. Am I correct in doing so (keeping M301 that in the first post I forgot about) or will the configuration of the machine be lost every time I turn off the HMI /PLC or does that happen in both cases? 

I would have done this test myself using the HW but I'm still waiting on it from the supplier and thought I would get a head start on this.

Thank you so much!

Andrei

[Andrei Blagaila 4]

I found a better solution reading through the recent post here. I keep the same momentary setting on the HMI and replace all with the diagram in the picture. But my question remainst. Once I shutdown everything what happens?

 

[Luke.S 8]

If L600 is ON when the PLC loses power, it will be ON when it turns back on. B1700 on the other hand will not retain an ON state and will become out of sync with L600.