Flex727
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Posts posted by Flex727
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You need to understand how Positive Transitions work. The only way for the PLC to know that the bit changed state is to have saved the state of the bit on the previous scan and do the comparison. On the very first scan of the PLC that is not possible since it has nothing previous to compare it to. You will need to rework your logic to account for that. You could do something like this:
Also, while I'm at it, you need to understand what Ladder Logic is all about. The program is divided up into ladder rungs purposefully to separate logic threads. Do not place multiple logic threads in a single ladder rung. It works most of the time, but can cause problems unexpectedly and is VERY poor programming practice.
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1 hour ago, Jeff164 said:
any parameters that the end user may have set up will be lost without the battery.
I'm not sure why this is a problem. Change the battery without removing power then reset the PLC. 24V power never needs to be removed from the PLC at any time during the process. Even if you feel the need to power cycle the PLC after changing the battery you won't lose operand values.
SB 300 can be used to reboot the PLC from the HMI screen without disrupting power also.
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The EX-D16A3-RO8 module would work for you and save you the cost of the EX-A2X. The EX-D16A3-RO8 is still a bit more than a EX-A2X + IO-DI8-RO8, but might be more readily available. (This is what Ausman is suggesting above)
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That should work fine, though I would use a Positive Transition contact for MB 20. HMI screen calls should be via transition contacts so they don't get called on every PLC scan. That's obviously not your problem since manually setting the bit works (and this is how I do it regularly with no issue). There's something else going on with your program. Post it here and we'll take a look.
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Better late than never! 😄
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On 12/4/2021 at 4:13 PM, Sideway said:
Though, in some of my ladder programs, i remember i used to put a direct coil sometimes in my leading net, which would turn red if the subroutine was ON.
Actually this does not tell you as much as you think. If it's a conditional subroutine call and the subroutine stops being called, the coil will remain on. This is only one of the reasons to never perform conditional subroutine calls.
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47 minutes ago, Jeff164 said:
The state Machine concept you showed me a couple years ago has simplified allot of what I'm doing
+1 on this. After learning the State Machine concept from Joe several years ago, I find that it is incredibly useful and simplifies many very complex programming tasks.
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Glad this is solved. I'll just place a reminder here to avoid conditional subroutine calls. This is poor programming practice when it can be avoided - and it nearly always can be avoided.
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Are you able to PING the address from a Command prompt? Also, did you confirm the address of the PLC in UniApps?
And, are you using a crossover cable or Ethernet hub?
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You just need a self-resetting timer, thus:
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Every time I download a project into a PLC, and sometimes when I open a project file, I get this error message:
I can just click OK and everything proceeds normally, but what is this telling me?
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All operands are retained through power cycle (if the battery is good). If you want them reset to a specific value, then check the little box with the power plug symbol. In your case, uncheck that box and your value for MI 6 will be retained and not reset to -600.
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I usually have a zillion windows and applications open that I am working on simultaneously, all set up the way I like, so rebooting the computer is always a last resort. I finally gave in an closed everything down and rebooted. Happily, that fixed the problem. Sure is a weird problem though and it would be nice to understand the cause.
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I opened an older project file this morning and it opened with none of the contact or coil symbols visible. Since then, all my project files look like this. I've tried opening files in other VisiLogic versions (using Version Swapper) and everything now looks like this. Anyone ever seen this? Anyone have an idea of what the cause or fix might be?
I am using Windows 10 on a high-resolution monitor. I've tried changing display resolution and font size, but no improvement.
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Terminals 7 & 8 are Analog Input 1, not Analog Input 0. Just move your wire connections over to 5 & 6.
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12 hours ago, Gabriel Franco said:
I use Function In Progress as a condition to SCAN block.
That is correct. Use SB 41 to SET a bit. Then use a Direct Contact of that bit, followed by an Inverted Contact of the Function in Progress bit, then your communications, then a RESET of the first bit, similar to below:
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Also, I'm not sure MB 1 is necessary (all the configuration and initialization will take place immediately before the program executes the next rung). What you might need is for SB 41 to SET a bit and use that bit (direct contact) to initiate your communication, with a RESET of the bit at the end.
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On 11/9/2021 at 1:01 AM, vasovas said:
like shown on the screenshot attached.
It is a problem, because it reset counters and I get wrong data collected.
Any suggestions?
Regards,
Taking a second look at this makes me wonder if you're not misinterpreting this. MB 0 shows to be on, but it does NOT show power flow to ML 0 and the others. Actually, it shows that ML 0 and ML 1 are NOT at zero and are NOT Reset.
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That looks like a Windows issue with folder permissions. Try moving the folder to a different location and make sure there are no read restrictions.
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I just started using version 9.8.81 and notice the following two issues:
1) When opening a project saved with 9.8.80, there is no notice that you are opening a project from an older version. However, when going to download the project to a PLC, it is required to upgrade the PLC firmware. If upgrading the project requires upgrading the PLC firmware, the programmer should definitely get a notice to this effect.
2) When downloading a project to a PLC, ANY change results in this message:
I am used to seeing this if there are dramatic changes or if downloading to a different PLC, but not every single download regardless of how small the change.
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27 minutes ago, Cordell Musser said:
I'm still learning things every day about Unitronics so every tidbit of info is valuable to me!
Aren't we all. 😉
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39 minutes ago, Cordell Musser said:
Even with putting SI 101 at a 10 power up value, I still have issues with getting the (210) error message.
But is it improved? That has been my experience. I haven't been able to get WAN connections to be as stable as LAN connections, especially with downloads across the Pacific, but it's tolerable. If you find other improvements, I would like to know of them also.
VisiLogic 9.8.91 bugs
in We're Listening...
Posted
Three problems with VisiLogic Version 9.8.91:
1) Constant "1Invalid operation at current state9" errors when opening a project or downloading a project.
2) No notification that you're opening a previous version project when opening a project saved with 9.8.80 (yet would require a firmware update if the project were to be downloaded into a PLC).
3) The "Note (218) The project you are downloading comprises many properties that differ from the project currently installed in the controller...." message ALWAYS appears regardless of how minor the change, thus rendering it useless.
These problems are all new to version 9.8.91 and did not occur with 9.8.80. Can we get them fixed before the next release?