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Posts posted by vamalgise
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Hello,
I was lately wondering will there appear any problems or synchronization issues when program created in Visilogic 9.8.9 is opened, saved and downloaded into Vision PLC in 9.8.31 version.
Or it is recommended to download it in the version of creation (in my case 9.8.9), i ask this question because in one of our work stations there is issue with Visilogic, version swapper usually gives errors and only reinstallation of Visilogic is helpful. So we open all our project in the newest version we used (9.8.31), but i ve been afraid to download the program changes in this version.
Is there any considerations or it is allowed to do it ?
Thank you
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Hello,
I operate 3 way control valve with 0...10V signal with analog output of IO-AI4AO2.
I linearize 0...100% signal from PID out to 0...4095 bit to analog output.
When PID signal is 0 and output is 0, i measure voltage in AO0 of IO-AI4AO2 and there is 9,3 V, when i give 100% signal, there is 14,4V on the output.
Obviously valve does not operate properly.
One more curious thing is that when PID out signal is more than 0, fault LEDs on the module start blinking ( AO short circuit and AI out of range) with specific frequency, like once in 5 seconds lets say analog input 0 goes to high limit value.
What could be the problem? Could it be some noise?
Thank you in advance guys.
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Hi Guy,
Yes, thats what i am talking about. When i select Last received phone number option, then PLC replies only to 2 of 3 operators. When third operator sends the command, PLC doesnt respond, but when i select to reply to operators specific phone number it works well. So i was wondering mby the problem hides in OS version, cuz i checked everything and havent found a solution.
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Hello i use Vision V350 for data acquisition and alarm system via SMS messaging.
I have 3 phone numbers in my config. When operator needs to know the status of the variables he sends the command message and V350 answers it via GSM modem.
Logically it should be like operator sends the request and PLC replies to this exact operator, so i set send SMS to Last Received Number.
For two of the numbers it worked well, but for third PLC didnt send back the message. Modem busy bit was active for some time and suddenly reset too early. dont know is it the issue with the number itself or anything else, but i had to make sure that the message comes to the operator, so i made it the way as if anyone sends the request the reply comes to all 3 operators. And it works well, but this algorythm is not good, as the messages bother people who didnt send the request and it is just too many messages.
I could not find any solution for long time and the problem is that this PLC is 100km away from office, so i dont go there very often. Then i noticed in SMS configuration there is a check box "OS 3.7.1 and higher". Is it VisiLogic version meant by this? And if my Visilogic is 9.8.9 and the box is not checked, could that be a reason for the failure? Or could you give other suggestions please?
Thanks
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On 8.2.2017 at 8:42 AM, Isakovic said:
In standard 3 point valves end switches are internal mechanism of stopping the valve, when it comes to end position it will stop moving. They usually don't have connection to external circuits, at least those I used so far don't.
Normal outputs are used for open/close, as you said it gets command to open/close as long as it is needed. Nets 14 and 15 from the picture are used for correction of virtual position because of the valve inertia. Let's say your virtual position goes to 0 but valve has 2mm yet to close, your system maybe won't be able to reach set point. Did you include this possibility in your program, looking at your problem it seems you didn't? If you check U90 example they activate close output for 2 minutes when PID reaches 0 to make sure it is closed, logic I use will send 1 second pulse every 20 seconds (or any other rhythm you see suitable) and the valve will get to 0 position, I find this method more stable (note this function activates when PID output is 0 and virtual position is 1-2%). Valve won't mind getting orders to close if it is already closed. The same goes for fully opened valve.
Do you have certain dead band for valve movement?
If it is possible you could measure the time it takes to open and the times it takes to close as Ausman suggested and modify your logic, but the difference shouldn't be that drastic that basic idea discussed couldn't correct it.
I don't know for better alternative to virtual position if you use valve without analog feedback. This is method other PLC manufacturers that have three step control function blocks use. Before this solution I used pulses where gap between them depended on the difference between SP and PV, but PID is more stable.
Do you have valve data sheet. What does it say for the units s/mm or mm/s? Check if you calculated moving time right.
First of all its s/mm, sorry.
I have 1% deadband for opening and for closing. It is not possible to measure the total time for opening and closing right now, because it is very low temperature outside and if i completely close the valve it is critical for the process, as it is district heating hot water pipe and the valve is very slow.
Now after reseting the pid and virtual position 1 week ago, the valve operates well and there is no problem. Implementing your part of the programm is good idea, i will try it and see how it will go.
Thank you both Ausman and Isakovic for help
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On 8.2.2017 at 4:37 AM, Ausman said:
Most actuators, even when modulating, dont mind working in tiny increments, that's what they're designed to do. But I don't understand your maths of 20 x 5 seconds = 1 minute. ?? Lots of start stop will generally mean similar movement to one long run.
The only way you're going to know where it physically is, is to fit the switches at least. Then to minimise the total checking time, force the valve whichever direction is theoretically closest to either switch until it trips. Then go the other way until the other one trips to measure things. And by "trip" I mean the change of switch state depending on which way you have it set up. From open to closed, or vice versa. And my point about valve running direction is important, due to the hysteresis ("deadband") inherent in switches. If you are running the valve one way the switch might change state at 48%, but if you are running it the other way the same switch might change back at 50%.
And I'd theorise that Isak has answered you on the pulse question already but it hasn't appeared online yet. Wait.
cheers,
Aus
Of course 12x5 i meant, my bad.
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7 hours ago, Ausman said:
Hi Vamal, welcome to the real world where specifications differ from actual operating conditions. Even the temperature of the medium alters running times on these things...and load conditions always mean there are varying degrees of flow resistance throughout the circuit. We've discussed this a bit and you could try the alternative method of timed pulses.
But it also sounds like you have been completely relying on the virtual position. You need to periodically force the valve to a physical endpoint and then resume your normal process. And you could build things into your program that check for unusual numbers and self-correct if necessary.
A possible alternative is to implement the 2 DIs and have them not set for endpoints, but measure them between a much smaller span more often. This wouldn't necessarily affect the output much if you set them close to the normal operational span, it would only take a minute or so to do. Then adjust your MAX according to whatever the maths works out to be. The bonus of this method is that you might get one of the DI tripping during your normal operation, which gives you a confirmation of where the valve is physically. and an edit: don't forget that the switches trip at different points depending on which way the valve is running.
cheers,
Aus
Yes Aus, i was totally dependent on virtual position, without calibrating the value.
I think your idea with auxiliary switch somewhere close to the operating area could be very useful.
Do the valve moves the same distance while the output is active for 1 minute or when the output is active 20 pulses of 5 seconds with lets say 1 second gap?
What do you mean by switch trip?
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1 hour ago, Isakovic said:
Oh boy.
Ok, this is how I deal with it. Nevermind the language.
MI210 - PID output
MI263 - Virtual position
MB206 - bit which tells output control subroutine valve is in end positionWhen PID is 0 and Virtual position is less than 11, use TD17 to close valve for 1 second every 20 seconds. I have a similar one for 100% PID output.
As i understood you do not use end switches in your valve, so it is very important to have correct PID output range (according to valve actuating time as you mentioned before).
The thing is that if PID out goes to 0 and virtual position will follow it very fast, it still doesnt guarantee that the valve is in the right place.
And one more question. Why is it important to use pulse output with a gap between the pulses? is it better for the valve mechanism? I only use output as long as it needed without pulses.
Thank you
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Hello everobody!
3 months ago i had finally launched 3 way valve 3 point control as was recommended by Isakovic, implementing virtual position.
The problem i faced was the difference between nominal actuating time (8mm/s, with 40mm nominal stroke=320s) and actual actuating time, which appeared to be more than that.
The issue was that when outside temperature was very low and water temperature set point was very high, PID was giving CV output 100% which in case of my actuator was set to 3200 (10msec) max PID output. But valve was opened only about 80% and PV was not able to reach SP.
I increased PID MAX output to 4000 and it seemed to be working well, but virtual position was always a bit bigger than actual and never correct. I had to calibrate it few times.
But one day PID stoped working giving status 5 (set point change in progress) and output went to 0. When i fully opened the valve manually, i calibrated the virtual position again to 100% and so far it works, but i am afraid that it is temporary.
Could you please advice me how can i change my system to avoid the control of the valve by virtual position?
Thank you! Vamal...
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On 10.1.2017 at 11:02 PM, Ausman said:
Hi Vamalgise,
Have a look at my post (no. 2) here:
The response you're getting looks exactly like what used to happen to me on installing the latest version of either Swapper or Visi. Go through the process carefully doing my steps and you should be ok. Any upgrade of any element seemed to stuff things up....my impression is that if you put in the latest Visi, you have to go to the latest swapper for it to be able to adjust things correctly during changeover. And in doing that, you have to tell the new swapper all the loads you want, and that's where my method makes it fairly easy.
Hopefully this will help. See how you go. Ohh yeah one last thing. Make sure you do each of the installs as run as admin as well.
cheers,
Aus
Thanks Aus, i did not mention that i also copy Visilogi_C and rename it according to the latest installed version, as you suggested. Only thing i did not do, i did not run installation files as admin. I always use Swapper which is in latest installed Visilogic pack in Visilogic_C folder.
Should i try to reinstall everything as an admin and which Swapper should i use?
Thank you
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Thank you Joe, Aus and Flex. Very useful info. Tried it today, everything stayed!
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Hello,
I faced a problem when i was downloading a project to Vision V570.
V570 already had existing project inside and i was downloading the same project but with few changes.
When download process had started pop-up window appeared with the following statement: existing project differs from the project you are trying to download. It is recommended to initialize PLC after download. Note: it will erase all the register values. Then it asks yes or no (sorry i wrote this statement in my own words as i didnt make photo, but the meaning is the same). Does it mean that if i press yes, it will initialize the PLC or it will ask again in the end of download? I was afraid to press yes cuz it is not acceptable to drop all the registers to 0.
Thank you.
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Hello,
I have installed many versions of Unitronics in my work PC as my company have controllers with different Visilogic versions programs. It came out that only version 9.8.31 works correctly. When i swap from 9.8.31 to 9.8.22 and then 9.8.22 to 9.8.9 it gives me following messages:
- Load 15Item cannot be found in the collection corresponding to the requested name or ordinal
- Run-time error'91': Object variable or With block variable not set
- Run-time error'5': Invalid procedure call or argument
- Load 12Type mismatch
- Run-time error'13': Type mismatch
- Run-time error'9': subscript out of range
I have found old forum topic about run-time error'9', where it is suggested to install Microsoft MDAC and JetDB from Unitronics CD, but i latest CD i have is 7.01 version and i couldnt find JetDB there at all. Maybe these programs could be downloaded from net or is it necessary at all? (here is the topic from old forum http://www.unitronics.com/forum_old/topic.asp?TOPIC_ID=1195)
NB! I run all the programs as Administrator!
Please help me with a good advice or any info, thank you.
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On 10/7/2016 at 0:30 PM, Ausman said:
Hi Vamal,
First up, it seems that you are in a bit of a bind with that actuator...it is one of the models in the Belimo range that doesn't have the modulating module option...not all of them do. However, more later on the fact that it does have a DO module.
Also, just making sure that you understand that I'm not saying change the valve, I'm saying just change the actuator.
If you can just change the actuator have a look at this: www.belimo.com.au/pdf/e/EV24A-SR-TPC_datasheet_en-gb.pdf
But......you have an actuator that is large, and therefore $ are higher if you choose to change it, which may influence your decision. But if you stick with Belimo (and I think they are good units) the only way in this size area you will get modulation seems to be to change the actuator. I would check with your local Belimo to make sure of this.
If you cannot change things at all, you could perhaps add the 2 x DO module. You could use this to get endpoint signals periodically, say every 24hours, which in theory then let you update your maths every day to work with theoretical position by checking the running time end to end. If the system has downtime this is simple, if it is on 24/7 then harder, but not impossible.
Theoretical/virtual position is in some ways not necessary anyway, if you move the valve and get the required result then you don't need to know where it is! But I have always found that modulation makes the process much smoother and is ultimately the easiest to implement.
Check with Belimo, they sometimes have more than the catalogue says!
cheers and good luck...
Aus
In my case, Aus, i have a plant where is an old PLC and i have to change it with V570, the principle of the customer is that it worked with old PLC and it has to work with the new one, without any replacement. The process is 24/7 non-stop, it is a district heating gas boiler house. The idea with 2 DO seams logical in case if the actuator does not move exactly as fast as it was designed to.
Thx mate
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On 20.9.2016 at 2:12 AM, Ausman said:
Hi all,
I am actually in the large HVAC game, and all of the valves I've encountered similar to what Vamal is describing work via one input moves the valve in the closed direction, and the other moves it in the open direction. Whilst writing this, Joe's answer has popped up, and he has described a way of doing it. As he and Isak say, you can do timed pulses and work on theoretical position.
However, in all of my instances I have given up on the actuator in question as you never really know where the valve is in it's span. I have always changed the actuator to a modulating type, which is generally very easy to do. I do acknowledge that some of the bigger valves have all of the actuation mechanism as a dedicated part of the valve body. But nearly all of the 3 ways I see in HVAC have an easily changed actuator. To save lots of headaches and enable much better control, I strongly suggest changing it. For most of mine it is a couple of hundred$ max.
There also is the cheaper possiblity that most actuators are able to have an add-on analogue output module attached. This is another way of achieving the same aim, but you end up needing 2 DOs and 1 AI and it is often easier just to change to the different actuator, which in my cases means I then need 1AO and 1AI. And for those who puzzle why an AI, my systems always check that the valve in question is responding correctly.
And an FYI edit: make sure the system is correctly balanced, to ensure smooth temp transitions.
cheers,
Aus
Thank you for your suggestion Aus.
In my case though i have no chance to change the valve and i must work with what i have.
And ATM the valve only has 2DIs for the open and close commands, Probably buying and additional AO module for the valve may make it simpler. What do you think?
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On 19.9.2016 at 9:50 PM, cantcliff said:
Do you have the make and model of the valve?
Here's my assumption right now.
The valve has an input to open and one to close. If you apply a signal to open, for 1 second, and then remove signal, does the valve stay open or does it close automatically, in which case, why is there a signal input for close. In my mind, opening the valve leaves it open until you specifically send a close valve signal.
My gut tells me to use the temperature as your variable to control the PID but it may have issues because you need to drive two digital outputs from the PLC for control in the PID loop and I can't see the logic to an effective way to do that in my head yet. But that's all dependent on how the valve actually runs.
*edit*
If all that holds true, then PWM won't necessarily work as intended.
I use the valve Belimo AV230-3, here s the data sheet
http://www.novreczky.eu/belimo/pdf/av2303.pdf
And yes it has 2 outputs: one for opening and one for closing.
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On 19.9.2016 at 2:58 PM, Isakovic said:
There is an example for PID loop in U90 ladder called "PID with motorized valve". You should check it out.
Idea is to have a register that will contain virtual "position" of the valve expressed in 1/10 of a second (you need to know time it takes for valve to fully open from closed position, this will be PID max output). You will then compare this value with the PID output, if it is smaller than PID you open the valve, if it's larger you close it. You should have a small deadband.
If output for opening the valve is active you increment virtual position register every 10ms (SB7). If output for closing is active you decrement it.
I used this before with Vison and Jazz controllers and it works well.
I have seen the example, thank you.
So it is not necessary to actually have a physical feedback from the valve? i do not really understand how to implement the virtual position.
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Hello,
My task is to control 3 way control valve in the boiler house to reach desired water temperature in the boiler house output.
I have a 3 way valve with 3 point control, means that it has 1 digital input for closing and 1 for opening.
Before i had another project with analogue control (0-10V) and i used PID autotune FB to send a signal to the valve according to ambient temperature.
With 3 point control should i use PID autotune output as PWM FB's duty cycle or is it otherwise?
Face with this type of valve first time, hope for advice, thank you.
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Hello,
If you put the controller into "STOP MODE", you should be able to program a new application into the unit.
-Detach power from the PLC
-Press and hold your finger on the screen
-Apply power while your finger is still on the screen
-Once the unit is powered on, tap once on the screen
-After the 10 second time-out, it should enter STOP MODE
-Establish communications with VisiLogic (remember, default baud is 115200)
-Once comms are established, program unit with new application
Please let me know if this helps.
Thank you very much, it helped!
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Hello,
I have new V570, i uploaded a program with nets to read registers from heat meter,
Probably i made some mistake with COM initialization, now i cant download a program or view the PLC in online mode.
I have completely no clue how to fix it or reset PLC.
Please help me, i cant attach attach my program, because its 20KB bigger than the limit ((
Thank you.
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In my country we use ";" as a delimiter. I tried to use delimiters HEX 28 and 29 which are ( and ) but did not give a result.
Check my project subroutine SD configuration, net 5, Would be easier than words. The way it is right now, it doesnt display brackets in .csv file.
Thank you!
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Hello,
I use SD card to log process variables to CSV file. For each file i first create CSV row with constant text to create collumn titles. I have to pressure values in my project, so when I try to name the column as P1 (bar), brackets are not displayed in CSV file, so the result is just P1 bar, is it a property of CSV file or a property of Visilogic? Maybe i need to use a specific delimiter to be able to use brackets?
Please give me an advice. Thank you!
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Based on the manual it is an error, but it's read related.
Have you tried resetting it after recording an alarm to see if it returns immediately?
I just tried it and it returns. And, sorry my bad, it is not read error bit 2 is Can't open file. The strange thing is that everything logs fine, alarms and csv file. Could it be because I also log a row in CSV when alarm occurs, so it logs alarm history and it logs row at the same time? But when I disabled that write row to CSV when the error occurs, it still shows the same status. What can be the problem ?
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There is a clear history buffer function block that you can enable when needed. It can be found under the utilities/ alarm menu in VisiLogic.
Thank you, Alex!
Downloading 9.8.9 Visiligic project opened in 9.8.31 Visilogic version
in Vision & Samba PLC + HMI Controllers & VisiLogic Software
Posted
Thank you Flex,
I agree with your vision about firmware and software versions and I always try to do the same, only issue was with Visilogic.
As I remember once I opened 9.8.9 program in 9.8.31 soft and forgot about the version differences, and it downloaded successfully, without asking firmware update.
But then I could not open the program again in 9.8.9.