Flickering text problem

[Maninashed]

Hi All,

I have a problem with flickering text on a Vision 430 (containing latest firmware). The brief video clip shows what's happening (fairly poor video but the problematic flicker is fairly accurately represented).

The screen field in question is a simple ASCII text field. It reflects a 40 character long text string in MI memory. That section of MI memory is absolutely static - no writing to it going on elsewhere. The ASCII text field setting is as simple as it can be - No Hide, Disable view, Marking view or Touch assigned to it. The amount of processing going on during the program cycle is minimal - only about 4 simple rungs being processed in the Main ladder, no subroutine calls, no routines executed whilst displaying the screen.

The text field above the flickering text is identical except that it is taken from a different part of MI memory, and it shows no sign of flicker.

I've had this same problem before with V430's but I've never understood the reasons. All I've managed to do before is to play around with alternative ways of displaying the information I want to display until I stumble upon a way that works without the flicker. At the moment this flickering renders the application completely unacceptable. This is part of an OEM machine which is currently being developed.

Any wisdom regarding why the flicker is occurring and how to stop it happening would be gratefully received.

[Ausman]

Flickering text is often because of an inadvertent overlap of screen elements, even if in theory the screen layout has allowed it.  Perhaps first play with sizing and try things with plenty of space b/n elements, to see if it helps.

cheers, Aus

[Flex727]

Please confirm you are calling the HMI display with a transition contact and not calling the display continuously.

If you are certain that the display is not being called multiple times, then try to download a blank project, perform Initialize & Reset, then load your project again.

[Maninashed]

Hi Ausman and Flex272,

Thanks for taking the time to reply. I can confirm:

1.    The display is not being called multiple times. The calling rung in the ladder definitely shouldn't call it more than once and setting watch points confirms that it is indeed only being called once.

2.    Tried the blank project download, initialise, reset, then proper project download, initialise, reset. This didn't cure the flicker.

3.    Tried many variants of spacing and sizing of the elements. This didn't cure the flicker. I also looked for any invisible elements which might be overlapping - there are none. Whilst moving the elements around, when swapping the positions of the two ASCII text fields, the flicker remains with the same element.

I also tried deleting the flickering element and then recreating it from scratch. Initially it flickered, then I resized it a little and the flicker disappeared. Good news I thought until I resized it again to the size I'd actually like it to be and the flicker reappeared. I've been unable to recreate the non-flickering case by further resizing.

I also tried deleting the flickering element then copying and pasting the other (non-flickering) element. This resulted in the copy flickering.

So, no further forward and extremely perplexed. Thanks again.

[Maninashed]

Exciting update...... (exciting for me at least)

After some excellent tech support from our UK agent (I4Automation - thank you Tony ), the problem was identified as the bit variable I'd randomly selected for the Link field in the ASCII string definition box. I don't need the element to be linked to anything but apparently you can't define an ASCII string element unless a Link is specified (the 'OK' button is greyed out if none is specified). I simply chose the bit which is set to indicate that this particular screen is being displayed thinking that it would always be '1' whilst displaying this screen and that all would be well. If it is changed to an unused bit variable the flicker goes away.

This seems like a pretty obscure nugget of information so I hope that some other frustrated person who is plagued by a stubborn flicker might benefit from this.

Thanks again and all the best.

[Flex727]

33 minutes ago, Maninashed said:

This seems like a pretty obscure nugget of information so I hope that some other frustrated person who is plagued by a stubborn flicker might benefit from this.

Thank you for reporting back on this. I've always found the Help file on this topic to be a bit ambiguous. Note the highlighted sentence below:

@Cara Bereck Levy, perhaps you could take a look at this and see if you think it needs updating?

[Maninashed]

I agree - the help file is definitely a bit fuzzy in this area. Not least because it seems to refer to some previous version of Visilogic. This is immediately apparent by comparing the image you've just posted from the user documentation with the image I posted from the latest version of Visilogic. I've often wondered whether I'm simply behind the times and if there is more up-to-date documentation out there somewhere. I've gone hunting for it on several occasions without success. It's a great shame really - In my opinion the Unitronics combined HMI/PLC devices are rather excellent and stand in a class of their own but the documentation is lagging behind somewhat.

[Flex727]

24 minutes ago, Maninashed said:

Not least because it seems to refer to some previous version of Visilogic. This is immediately apparent by comparing the image you've just posted from the user documentation with the image I posted from the latest version of Visilogic. I've often wondered whether I'm simply behind the times and if there is more up-to-date documentation out there somewhere. I've gone hunting for it on several occasions without success.

The Help file often refers to the "Standard Vision" product while what you have is the "Enhanced Vision" product. They are functionally almost the same - mostly some added features and capabilities. Usually, when needed, the entry will simply mention the differences between the two products rather than have a totally separate entry for each (the same VisiLogic program is used for both product lines). In the interest of keeping costs low, I think this is justified.

29 minutes ago, Maninashed said:

In my opinion the Unitronics combined HMI/PLC devices are rather excellent and stand in a class of their own

I agree. This is why I stopped recommending other brands to my customers some years ago and now only accept work for Unitronics PLC programming. The software is great and the documentation is good enough for most needs. Since this software (and documentation) is free, I can understand why they don't have an army of technical writers keeping everything perfectly up to date.

[Maninashed]

Ah! It becomes clearer. Whilst I knew there was a distinction between Standard and Enhanced I didn't realise that the user documentation was based upon the Standard variant. I think that some of my trouble is that I generally seem to push things like PLCs to their limit and so I get into the more tricky areas of operation which might show up the holes in the documentation or perhaps might need a bit of assistance from a wise one on a forum somewhere. Still, I always aim to turn out a blindingly good product and so I think that the effort is worth it in the end.

[Flex727]

If you have an example you can share, I'd love to see it. I'm always looking to learn from top-flight programmers. if so, PM me.

[Maninashed]

Top-flight programmer huh?! I feel honoured even at the very thought of being a top flight anything - thanks for the boost! PM comment noted.👍

[Cara Bereck Levy]

On 4/22/2022 at 9:04 PM, Flex727 said:

The Help file often refers to the "Standard Vision" product while what you have is the "Enhanced Vision" product. They are functionally almost the same - mostly some added features and capabilities. Usually, when needed, the entry will simply mention the differences between the two products rather than have a totally separate entry for each (the same VisiLogic program is used for both product lines). In the interest of keeping costs low, I think this is justified.

I agree. This is why I stopped recommending other brands to my customers some years ago and now only accept work for Unitronics PLC programming. The software is great and the documentation is good enough for most needs. Since this software (and documentation) is free, I can understand why they don't have an army of technical writers keeping everything perfectly up to date.

There is a Help topic explaining the difference 🙂
And unfortunately...no army of tech writers... 
I do try to fix issues called to my attention.

> I don't need the element to be linked to anything but apparently you can't define an ASCII string element unless a Link is specified (the 'OK' button is greyed out if none is specified). I simply chose the bit which is set to indicate that this particular screen is being displayed thinking that it would always be '1' whilst displaying this screen and that all would be well. If it is changed to an unused bit variable the flicker goes away.

This seems like a pretty obscure nugget of information so I hope that some other frustrated person who is plagued by a stubborn flicker might benefit from this.<

I have put this on my to-do list - I will try to clarify the topic for the next version 🙂

[Flex727]

17 minutes ago, Cara Bereck Levy said:

And unfortunately...no army of tech writers... 

Cara, you are indeed a one-person army. As always, thanks!

[Maninashed]

16 hours ago, Cara Bereck Levy said:

I have put this on my to-do list - I will try to clarify the topic for the next version 🙂

Splendid stuff -feedback from the user straight into the user documentation!

Thank you both.