Flex727

Outstanding explanation, Damian! I have been tripped up by that before and never really thoroughly understood what was happening. Very helpful post.

Joe, that was a great example - thank you for posting the example program. Just one more question: how do you normally handle placing the machine into the initial idle state (MI0 = 10)? Would you normally set the "Power-Up Value" to 10 or use some logic to pre-determine which state the machine should start up in?

Thanks for the helpful suggestions. Here is what I ended up with for the "Master" PLC. Perhaps this is a bit unwieldy, but it seems to work well. I broke the comm error up into two parts. If the Socket (3) isn't initialized, I re-initialize the ethernet card and socket then try to connect the socket. If the socket is initialized, but not connected, then I skip the initialization step and just try to reconnect the socket. For each, I re-attempt every 2 seconds. This seems to handle the varying circumstances well - if both PLCs are connected to a hub or switch, then where the loss of communications occurs results in different situations. The MB125 "Comm Error" bit is the same logic as I showed in my initial post, above.

I swear every time Joe Tauser makes a comment on this forum I learn something. Joe, can I trouble you to elaborate a bit on what you mean by "I use a pointer register and equal blocks to jump between states and the subroutine is always called when the state machine is not idle; this way the coils will get written properly and not be left on when I leave the subroutine"? I think I understand the first part - each state has a number associated with it and you call the subroutine when the state equals a specific number, but I don't understand what you mean by "the subroutine is always called when the state machine is not idle; this way the coils will get written properly and not be left on when I leave the subroutine". Also, what is included, generally, in the "beginning 'idle' state"?

I'm sure someone more authoritative will come along, but in my experience, any coil in a subroutine that is not executed will remain in the state it was in when the subroutine was last called. This is similar to and would be the same for any operand in the PLC that has no coil associated with it at all (i.e. remnants from a previous program) - they will always remain in the state they are in until a ladder rung with that coil is explicitly executed. This is why it can be important to initialize the PLC when loading a new program.

Excuse me for bumping this topic, but I was hoping there would be somebody out there with some experience to share. Thanks.

I wonder if any wise programmers might have some helpful hints. I've been programming for awhile, but I'm still a bit sketchy about networking. When I have two v570 PLCs communicating with each other, it's important to know (and potentially correct automatically) when a communications error occurs. I'm attaching a subroutine example in the master PLC where I communicate with the slave and detect a comm error by looking for a change in the count of data received to the socket (SDW21, for Socket 3) - ladder rungs 5-7. Currently I initiate communication every 250ms and if I go for 2 sec without the RXD count increasing then I alarm. This seems to work well, but is there a better way? Also, when a comm error is detected, what is the best procedure for making an attempt to re-establish communication automatically? Thanks. By the way, I'm using VisiLogic 9.4.0, if it matters, and communicating by MODBUS IP over Ethernet.

Thanks, I should've mentioned that I'm using a v570.

Is there any way to create a slider bar on the HMI that would control an MI smoothly between two values? An example might be to control the screen brightness by varying SI9 between 0 and 100 with the slider controlling the value.

Thanks, Cara. I had that set up on my previous laptop, but haven't set it up on my new one yet. My recollection (which may be faulty) was that I couldn't copy and paste between separate instances of Visilogic, but had to open a project, copy the elements (either HMI or ladder), open a new project (which closes the previous one, of course), then paste it in. That works, but is extremely cumbersome. It seems like I've heard about a simulator being "in progress" for a couple of years now. Is it really - or has it been dropped? The v570 PLC HMI with only 320x240 resolution is so far behind the times that it's very difficult to explain to a customer. At that resolution the interface always looks much less professional than it could be and complex screens are often impossible to produce correctly. This leads to a much more clunky interface by having to break screens up in a way that is not always logical or representative of the equipment being controlled. I strongly recommend that Unitronics take a look at developing a 5.7" 640x480 product. Since Visilogic already handles the 640x480 10.4" product, I can't imagine this would be a very significant engineering undertaking. I'm sure it's more of a marketing question and if your research says there's insufficient demand for such a product, then that's a legitimate answer.

It would be helpful to mention what operating system you're using, what brand of USB-to-serial converter you're using and what version of Visilogic you're using. However, the most likely culprit is the USB-to-serial converter. Unitronics has some specific recommendations that you can find elsewhere on this forum. I am currently using a Trendnet TU-S9 with my Win7 laptop and it's working very well and reliably.

I've been using and programming Unitronics PLCs for several years now and I have to say that I absolutely love them. I always recommend them to my customers whenever I have the opportunity. However, there have been a few missing pieces that every user really needs and wants. I know this has been asked many times before, but it's been awhile so can a representative from Unitronics provide a quick update on the status of these issues? I realize it may not be possible to get too specific, but a simple "we're working on it" or "there are no plans at this time" or "we're working on it and we should have something really soon!" for each item would be great to see. -PLC simulator built into Visilogic -Online editing capability -Ability to open more than one project at a time and directly copy and paste between projects. -Ability to see both ladder logic and HMI screen simultaneously in Visilogic. Also, is there any plan to introduce a 5.7" format PLC with a 640x480 screen resolution? The limitations of a 320x240 screen are sometimes extremely difficult and my customers do not have room for the larger format (10.4") PLCs. Most of your competitor's HMI screens that are similar size as the 570 are 640x480.

My laptop is an HP - maybe it's an HP thang. By the way, Cara, I think changing the Windows font setting to 100% from the default 125% seems to have also solved the problem I was seeing with delays during HMI editing.

Cara, once a program is loaded into a new PLC I never see the splash screen again - should I? However, I didn't realize it was so easy to change - thanks for the info. Emil had what I was looking for and that worked perfectly. Thanks! (to both of you)

I have a need for the first screen that the user sees be something other than the "Start-Up" screen that the 570 defaults to. I remember reading something about how to handle that at one time, but can't find it now. Anyone have a suggestion for best practice on how to do this? I've tried SB2 and that didn't work. I've even tried a negative transition on SB2 and that didn't work either.

Damian, what is your screen resolution? I wonder if, similar to what Cara was mentioning, Win7 decides to default to 125% on computers with higher resolution. I specifically ordered my 15" laptop with 1920x1080 because I wanted more pixels available for Visilogic. I wish I could find one even higher (without going up to 17").

I've been poking around in Windows 7 and found the problem. In the Display settings there is a setting for text size. This, of course, is not new to Win7, but at least on my computer, it defaults to "Medium - 125%" instead of 100%. this had the effect of increasing the font size in Visilogic. I hadn't checked this because I had never changed it and assumed the default would be normal size rather than larger - stupid me. This may also have an impact on the delay times when moving or deselecting HMI elements - I'll check and report back.

As I said, I'll send an email to support, but here is the screenshot for those interested. The left side was taken from my WinXP desktop PC running Visilogic 8.6.3 with a screen resolution of 1280x1024, the right side is from my laptop running Win7, Visilogic 9.4.0 and a screen resolution of 1920x1080. I think it's clear why this is a problem.

Thanks, I'll do that. But how about the simple question about how many lines of text are displayed in the operand description box? My desktop computer runs WinXP and Visilogic 8.6.3 with a screen resolution of 1280x1024 and I get 3 lines in the operand description box. My laptop runs Win7 and Visilogic 9.4.0 with a screen resolution of 1920x1080 and I only get 2 lines. What determines this? This is a very simple basic question that someone at Unitronics should have an instant answer for, at least it would seem to me.

Thanks, Damian. I thought I had seen at least one previous post on this, but was unsuccessful in searching for it. Unitronics Technical Support: Is this a known problem? Do you have any suggested solutions, or is this just a conflict with certain computers that is too rare to spend any time on to correct? How about the issue of only 2 lines displayed in the operand description box? Anything I can do about that? Thanks.

Unfortunately I've made two changes simultaneously and I don't know what is the culprit. I had to replace my laptop - the old one was a Win XP, 32-bit, that was several years old, running Visilogic 8.6.3. My new one is Win7, 64-bit. I'm now running 9.4.0 and editing HMI screens in Visilogic is excruciating. Granted, it certainly wasn't a speed demon before, but every time I click to select or deselect an object on an HMI screen can take several long seconds before I get the cursor back. If I have several objects selected at once it can take 10 or 20 seconds or more just move them one pixel, depending on the complexity of the objects. This new laptop is fully decked out with the second gen Intel Core i5, 8GB Ram, etc. It is FAST with every other piece of software I own. Noticeably faster than the previous laptop, but not with Visilogic. Any suggestions on what is slowing things down? I've got to get this fixed to get my productivity back to where it needs to be. Yes, I have disabled UAC. Another problem is that the operand descriptions in the box in the ladder section are only two lines (the address, e.g. MB50, plus one line of the description). Before, I had three lines total - the address plus two lines of description. Is there a way to control this? It's extremely frustrating to have to hover over every operand to figure out what it is.

Emil, users have been BEGGING for this, along with online edits, for many years now. Do you think the idea of a simulator will advance from the "thinking" stage to the "planning" stage anytime soon?

Thanks, Simon. I'll check that stuff out when I go back to that customer site. I did offer them another option to repair their problem and if they don't want to avail themselves of that option, I'll have to return for further troubleshooting.

Sorry for the delayed response. I appreciate the help. Here are the answers to Simon's questions: Wiring and setting appear to be correct. I/O modules being used are: EX-D16A3-TO16 IO-D16A3-RO16 IO-D16A3-RO16 IO-DI16 All the outputs work correctly when following the ladder logic in run mode. We had what appeared to be a failed relay that I wanted to troubleshoot. It was connected to the first I/O module and was the only output being used on that module. That module had a bunch of inputs and the other modules were also mostly fully utilized with both inputs and outputs. My intent was to connect the relay to another I/O module with an unused output and then see if I could force it on and off while online with the PLC. Yes, I tried several and got the same results with each. When an output showed "0", I would force the output to "SET", the glasses display would change to "0<1>", but the I/O module corresponding output would not be lit and the force pushbutton would still display that the output was off. If I forced the output back to zero ("RESET"), the glasses display remained the same: "0<1>". I don't really understand this. An unused output has no coil in the ladder logic to set/reset (I do NOT want to add the coil and download the change to the PLC). Or perhaps we're just talking past each other - when I say "force", I am referring to the little box that pops up with the state of an operand when it is clicked in the ladder or in the operands section at the bottom of VisiLogic when online with the PLC. For regular operands (MBs), if the bit is off the pushbutton will say "SET" and when it is on the pushbutton will say "RESET". For Inputs and Outputs the pushbutton will say the same thing but it is "greyed out" and you have to right-click to select "SET" or "RESET" to force the Input or Output one way or the other. By the way, forcing inputs this way works perfectly, but outputs give me the result I describe above. Bottom line, what I need to understand is, am I correct in my understanding that I SHOULD be able to force an Output in the manner I'm describing? If so, what should I be looking at to try to understand why it does not work the way it should. Thanks!

Just bumping this topic, as I'm sure there's a simple answer. What does "0<1>" mean in the online display of an output after I've attempted to FORCE it ON? And why can I not FORCE an Output when I'm online with a v570 PLC?