FireNeck

Hi JoS0, I don't know if I understand correctly what you mean, but I assume that you set up the the PID only with help of the PID FB "RUN Auto Tune". So the PLC tries to find out the values for P, I and D itself and stores them. I do it differently: I set a Positive Transaction of SB2 (Power Up) and as second possible condition a positive transaction of a MB (Manual Config, e.g. MB10) to trigger the PID FB "Configuration". That way the power up bit or the Manual Config Bit can run the Configuration of the PID with my entered values for Setpoint, Upper/Lower Input/Output Level, P-Value,I-value, D-value, sample time. With linking MIs to values for P, I and D I can change these values and after changing them can trigger the Manual Config Bit to do the Reconfiguration of the PID. It's important to have the PID FB "RUN PID" in your program to have the PID really work, but I think you found out that on your own... After that explanation you see what I meant by saying to "play with the values": I do a config with some set values, let it run. If it's too fast, I change e.g. the P-Value, do the reconfig, watch it. If it's OK, I let it be, if not - change some more or something else like I-value, reconfig, watch, ..... You know trial and error. In my opinion the PID FB "RUN AUTOTUNE" is not suitable for systems with slow reacting responds like water flow, heating/cooling big amounts of water and so on. I generally do it without the "RUN AUTOTUNE" and only use "CONFIGURATION" and "RUN PID" FBs in my applications. That way I have total control for the PIDs and their behavior, working with Error Integrals and so on, See in help file for more information on the topic of error Integrals. Hope you can get to a solution with these tips. Good luck FireNeck

Hi AZ1975, please don't shout, we'll hear you... I found that there are two ways of using HMI built for bigger screens on a smaller screen without crashing: 1. Don't call them - works fine, but I think is not what you used 2. Re-Edit the screens. Means, if there are buttons or frames or anything else that would not be visible on a V570 when using a screen made for V1210, the PLC will definetely crash. You have to rearrange the screen so that everything is visible on a V570 screen. No workaround on that, I'm sorry. Hope that helps FireNeck

Hello Jo, I don't know exactly if I can help, but at least I can share my experiences with Unitronics PID. First thing first: I saw that your Output Limits are set to 820 to 4000. You wrote that you want to go with 0 to 10 V, that would be 0 to 4095 in Units for the AO, but that was just something that came to my attention. But be warned, by limiting the output to 820, you will never fully close the valve (just to say). But going to the PID itself: I found it easier to limit the action to P and I only, so mostly I set the D value to "0". Next thing is: as described in help file: If the P value is small, the ragulator will react quicker, if you increase P value, it slows down a little bit. Same for I value, if it's small, it will react very fast, if its high, it will react slower. For example: If I have to drive a compressor with a VFD which has to be quick, my normal setting would be like P = 150, I =2, D=0, time = 10. This means that the regulator will react fast to hold the pressure at the desired level. If I have to regulate a valve, I normally slow down everything like P = 500, I = 15, D=0, time = 100. Most time's it's a little trial and error to find the best settings, but when optimizing you should start with changing one parameter only (like first P value a little bit up or down, after that playing with I value). As stated, I think most in most cases you don't need the D value. I saw that compared to the first post, you did set higher and lower input range. I think you should extend the upper limit even more and go to like 600 (60 °C) as you have a maximum of 90°C possible. Then start trying to set D to 0, start with P = 300, I =15, sample time 60. See from there how fast or slow it reacts. It's also important to see how fast can the valve work (0 to 100%, what's the time there ?), because it doesn't makes sense to rise and lower the output value fast if the valve is not able to follow. Hope this might help. I don't know if these tips are helpful with PID-Server, I only use PID in my logic with values changeable via HMI. Good Luck, FireNeck

Hi Mike, thanks for your quick response. Seems that I should stop guessing and start reading help file more intensely.... My fault, answer received, topic closed. Thanks again FireNeck

Hello Simon, yes, you're right as far as that there are older versions of OS in the folders of the older VisiLogic versions. But there is always just one older OS, or let's say "the latest OS for the compatible VisiLogic Version". Just an example: in the folder for VisiLogic 6.01, the OS therefor V570 is 1.02(08). But I need for some old PLCs in use OS 1.02(01). Another Example: VisiLogic 9.3.1, V1040. OS installed on the PLC is 3.03(00), latest OS in folder is 3.03(16). For troubleshooting it would be nice to have the old OS files so that it's possible to see if the change from like 1.02(08) to 1.02(01) has an affect on the program running or not. Believe it or not, I had a system which was not able to run at 1.02(08), but with 1.02(01).Don't ask me why, but you know "Never touch a running system !" As for the table it would be nice to at least see, which OS is "connected" to which VisiLogic, so that you don't have to search all the folders which OS is combatible to which VisiLogic. Maybe it's just a luxury problem which only I came across, but you know, there has to be something to complain about so that Unitronics always has something to do.... But thanks for your answer anyway, I didn't realize at first that there is OS in the VisiLogic Swapper folders. Thanks, FireNeck

Hi at all, just a quick question: As I have to upgrade to VisiLogic 9.5.0 due to access our newest software, I am missing the 9.3.1 swapper version. It's just not listed at the website. Could Unitronics load it up, so that I can securely acces my "older" versions installed at other sites with 9.3.1?? Thanks FireNeck

Hello to everyone, just a short but in my opinion important question: Is there a compatability table out there, which VisiLogic version is working with which OS on which PLC?? It's just a thing (to me) as often Unitronics recommends on having the latest OS installed and having the latest VisiLogic installed.... I mean, for sure, it's (mostly) the best to have everything up to date, but seriously, having about 60 PLCs out with remote access to only 30% of them, and just going to "let's update them today" just to find that something's not working the way it did before is not a favorite usage of work time to me. Just an example: I had a PLC working fine when program was on (written in 9.3.1). Then it seems, someone uploaded a newer version of that exact same program (two MBs added) with 9.4.0 .... suddenly i couldn't use the display keyboard to enter values (despite the fact that the PLC went to STOP-Mode without showing errors) - no let me correct that, it showed me the place where I could enter them and i was able to press on the screen so that something would be entered, but I don't know what I entered as the complete keyboard was invisible. I had to reupload the program by using 9.3.1 and additionally had to downgrade the OS from 3.6(03) to 3.4(16). Now it's working, but nobody knows why. So, would be nice to know (e.g. in a table) which OS is compatible with which VisiLogic on a PLC. Also would be nice to have a download section for older OS, Boot and BinLib versions, to be able to downgrade for testing purposes and/or troubleshooting. Thanks and have a nice day, FireNeck

Simon, as for your questions what I can say so far: - the read operations have never been a problem in the old installation, only sometimes the write operations - in the ladder software, there is used before every operation a negative contact of "Function in progress"-Bit, after the "Read Holding Register" function for example, we jump to another step, where a counter is incremented if the Function in progress bit is negative and with the positive contact of SB15 (100 ms coil), until counter reaches 20, then we go to next function (read or write), so the time delay to wait for an answer should be long enough. That's also easy to follow up, as the MI for Status Messages is "4" at first, then switching to "5", after going to the next operation starts with "4" and so on... - cable length : Slave3 - 20 meters - master - 23 meters - slave1 - 4 meters - slave 2 - cable type is double shielded twisted pair, all the same type, no mixing. If you want to know the exact name of it, I can tell you after I have checked on site. But as we use this cable all the time for the ModBus directly over RS485, and never had problems with it, I personally don't think that this really could be the problem. Thanks for the detailed questions and advices so far, as mentioned before, I will go test it further when having another converter and going to the site to investigate some more. best regards FireNeck

Joe, Simon, thanks for your advices so far. When I'm able to go to the site one more, I will try this out (even though I already tried with one terminator off without success), but we'll see. Concerning the part of having A und B signals inverted somewhere: As stated in first post, the exactly same cabling was used to communicate ModBus to the slaves with the V260 before, but with a RS485 card installed at COM3, which now has been removed for Ethernet-card on COM3. As it was working back then(at least 70% of the time, as long as the ModBus function was processing the read operations, but went to fault at the write operations randomly) I assume that this is not a cause of trouble. Also as stated, when trying to change A and B signals at the converter, nothing is received by the slaves - I love RX and TX LEDs on communication devices ! ;-) But however, I will try everything that may help me. (Got myself two different ModBus Master software freeware versions for testing now). But I have to wait a little bit, as I don't want to visit the site without another (completely external powered) device, as it's everytime a trip of two hours - one way - which nobody is gonna pay to me if failing again... Will get back to you if I know more .. or less .. or whatever ... Regards FireNeck

Hello Simon, once more it's me. So I tried with a RS232/RS485 converter. It's a device from third party, which allows powering from RS232 and optional powering from another source (it's USB as it's built to connect a PC to e.g. a ModBus-net). So after about 2 hours of trying with no results, I changed the complete setting from COM2 to COM1 on the PLC and after the PowerUp, it was running .... at least for 10 seconds (the read acknowledgement counted till 26) and it was gone again.... What was very confusing to me: when watching the slaves (3 in this case) I could see that the slaves receive the messages (the RX led there lights up periodically) and also start answering when it was a message for them (TX led starts lighting directly afte the RX). So, the nodes answer, but the PLC don't recognise it. At first I was thinking, maybe it's aproblem with the powering from RS232, but there was no change with the additional external powering. After that I thougt it may be a problem with the pin connections, but as it was working, for 10 seconds, that couldn't be the problem either. So, is there a buffer I can directly watch when it comes to send/receive (some SDW or SI) ?? To explain the hardware: It's a RS232 to RS422/RS485 converter from "Exsys" (EX-47900). I connected it to the PLC with the programming cable and a gender changer (male/male) and a null-modem-adapter (the slaves got no messages without the null-modem-adapter). On the RS485 side there is double shielded twisted pair cable installed, with termination on both ends. The PLC is in the midst, meaning that in 2-D it would be (termination:slave3 - PLC - Slave1 - slave2:termination). Everything connected with RS485-2Wire. So if anyone could give me a hint why it's not working, or why it worked only 10 seconds or why the PLC doesn't seem to recognise the answers from slaves, your help will be greatly appreciated !! best regards FireNeck

OK, thanks for the info, Simon. Let's assume i put an external converter RS232/RS485 (bidirectional) inbetween. Do I have to change my code concerning modbus RHR and PHR and so on? Or is it just changing the port setting from RS485 to RS232?? Could I use the programming cable to connect to that external converter? Any suggestions on that? Reason is: at this V260 there was a V200-19-RS4X installed for the RS485. We replaced it with a V200-19-ET1 to have better remote access to the PLC. Now we face the problem of having no ModBus Communication to the 3 external devices we want to gather data from.... Thanks for your help, it's much appriciated

Ok, thanks for the info, so no jumpers around. But can I use the port for ModBus RS485 communication or is COM2 RS232 only? Thanks for your help so far! regards FireNeck

Hi @ all, I have just a short question about the hardware of a V260-16-B20B. When reading the installation guide, there is stated, that the COM2 Port could be used either as RS232 or RS485 port. One should be able to choose if it's 232 or 485 by changing jumpers on the inside of the OPLC, right next to the COM-Ports. As I opened the OPLC to install an Ethernet-Card on Port3, I wanted to change the COM2 Port to RS485 by jumper selection, but there is none .... So, is it not necessary to have jumpers switched on V260-16-B20B or is it not possible to use it for RS485 Modbus Communication on Port2 ??? Thanks to you guys, FireNeck

Hi Emil, thanks for the suggestions. I was also in contact with support and when they tried to duplicate the problem, they hadn't any, so I was guessing and testing around. Support also told me to check the OS version (mine is rather old it seems). I tried increasing SI59, but the programm didn't accepted my entry, always stayed at 0 ... interesting though. But now to what I found out: I was connected to the PLC through VPN-Tunnel, cause the site is some distance away. I always tried to send the eMail, while still connected. I found out that this circumstance messed everything up. So I tried to trigger the sending with a delay of 2 minutes. So: started the timer, loged out, closed VPN-Tunnel; 2 Minutes later I had a nice eMail with the attachements perfectly and complete, so that was the real problem. As often, the biggest mistake in program: the user ! ;-) So, just came back to tell everyone what could be a problem if they have one with similar issue. Thanks to you, Emil and support, so long, FireNeck

Hi again, no ideas from your side? I now played a little with all this stuff (eMailing) and something suspicous showed up: While sending the file from SD-Card, the SI66 changed from 0 to 1 (indicating "SD Card Read:End of File"). Also the file I received was only 10kb, another try only 2kb in size, but when confirming by looking at the SD-Card directly with SD-Card-Explorer, it shows me that the file size is 101kb?? I checked SI58 (email file attachment size) and adjusted from "1024" to "500" for testing purposes, but the result was the same. Interesting thing also, aside from changing the value at SI58, everytime I resend the email, the attachment file has different sizes, even withour changing anything at SI58. So, any good ideas for this ? Thanks FireNeck