Penko Mitev

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About Penko Mitev

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  • Birthday 06/17/92

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  • Website URL http://kms-e.com
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  • Gender Male
  • Location Plovdiv, Bulgaria
  • Country Bulgaria
  • Interests Hobbies: Computers, PLCs, Mechanics<br />Women, Cars, Offroad.

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  1. Develop a fieldbus for modular IO

    I second you :P
  2. Develop a fieldbus for modular IO

    Bob, thank you for the detailed reply. In fact, I will go for a quote from OMRON for the components you specified. Of course, what I want most is fast programming, reliable fieldbus, high speed. This is a large project, so adding several thousand bucks is not big problem. That's why we did a general estimation of what would such a fieldbus network cost(the maximum) and we included it into the quote. Now, there is flexibility to choose our provider. Twido with the TwidoSuite software is perfect for up to 100 I/Os. Take a look, you won't be sorry.
  3. Hello all! I have troubles establishing communication between Weintek MT6070iH and Schneider(Modicon) Twido. I admit the post is little longer at a glance, but if you take a closer look, it mainly includes settings. I just want to explain everything in a very descriptive manner so everyone understand what I have tried to do and probably understand why it’s not working . Here is some specification of both devices in order to clarify how should things work: Protocol: Modbus via RS-485(2W(wire)). Baudrate: 19200 Parity: None Data bits: 8(RTU mode) Stop bits: 1 In the Weintek software: • PLC Type: MODBUS RTU • PLC device number: 5(This is used as address for the Modbus communication) • RS-485 2W • First COM1, then COM3 with the settings above for baudrate, parity, etc… In TwidoSuite, in addition to the PLC and its expansions, I added a “General Modbus Element” which is actually the Weintek HMI. I created a link between it and Twido. Here are the settings I adjusted in TwidoSuite: • Twido Port configuration – Modbus, Address @5(This is the address, therefore we set to 5 as we did in Weintek Software) • Link configuration – using the same settings above for baudrate, parity, etc…, calling the network “PLC->HMI” • General Modbus Device(the Weintek HMI) – Master I followed the “Modicon Twido” wiring diagram in the PLC connection guide PDF which comes with the installation of the Weintek Software. I made two cables one after another, to test things out, but neither of them worked for the communication. Here are the wiring schematics of both cables: Here is a link to the wiring diagram, but I include it as a text also: ftp://ftp.weintek.com/MT8000/eng/UserManual/plc_connection_guide.pdf Page 234. Weintek COM1 RS485 port  Twido 8 pin miniDIN port Pin 1 RX- Pin 2 B(-) Pin 2 RX+ Pin 1 A(+) Pin 5 GND Pin 5 DPT, Pin 7 GND. Connecting these pins tells Twido that we are using the port for MODBUS and not for the protocol used for programming the PLC. Weintek COM3 RS485 port  Twido 8 pin miniDIN port Pin 6 Data- Pin 2 B(-) Pin 7 Data+ Pin 1 A(+) Pin 5 GND Pin 5 DPT, Pin 7 GND. Connecting these pins tells Twido that we are using the port for MODBUS and not for the protocol used for programming the PLC. According to my opinion, everything is to be watched from soldering side. This is the way I have done things. After adjusting everything, I decided to upload both the PLC and the HMI applications to the devices and see if everything works. Unfortunately, no communication was established. The red “COM” lamp on the HMI was just blinking from time to time, but there was no persistent activation. I noticed that, if create a “Toggle” button, it is no visible if there is no communication from the PLC we have specified for this button. After having no luck, I decided to try “ASCII” mode, because I noticed the wiring schematic is the same. When I started the HMI, the “COM” lamp was activated and there seemed to be some communication between the Twido PLC and the HMI. I was relieved because maybe I had finally solved it. I added several buttons to the HMI application and re-uploaded it, but by clicking them, there was no result. After a few minutes of tests, I noticed the “COM lamp is no longer activated and I couldn’t reproduce the situation in which I had this “strange” communication. I would like to say, that this is the first use of MT6070iH Weintek HMI and maybe the forth use of Twido for our machines. On our previous machine, we installed the legacy HMI Weintek MT506TV. It used the same settings, the same diagram for soldering the cable and it works properly until now(it’s 2 months since we installed it). There is no logical explanation why these wiring diagram and settings would work perfectly on the legacy MT506TV, but would not on the new-generation MT6070iH. As for the cable, it’s just 1 meter long, therefore I didn’t select a “shielded” one. However, I do not think this is the problem. Okay, now to the questions. Does anyone ever used this combination of devices – Schneider(Modicon) Twido and a Weintek HMI? What wiring diagram and settings did you use? Was it a new-generation MT6000 HMI or an older model? And some general questions – What is the best way to test MODBUS devices – PLCs, HMIs, other? How can I detect which device is the one not properly configured? Maybe some MODBUS testing devices, which I can use before cold starts? What would you recommend? Thank you in advance! Penko
  4. Develop a fieldbus for modular IO

    Guys, sorry for not answering immediately about what happened :). In fact, we have a much bigger reduction in price from Schneider than the other PLC brands we work with. Therefore, I prefer using Schneider for this project too. I contacted Schneider Bulgaria and I was given offer about the components. We have to use about 50 Remote IO modules, 6 inputs/6 outputs each. The sales agent also included a Modicon M340 PLC because he told me Twido can't support so much IOs. I say Twido, because it is still the only Schneider PLC I have experience with. He knows this and was fast enough to tell me before asking the question :). Actually, in the inquiry, I told him there will be 35 modules. Unfortunately, after estimating precisely and after the customer added a request for additional functionality, we stopped at 50. The sales agent told me it would be much better if we create two MODBUS networks so there are almost equally big. Additionally, we will have a Variable Frequency Drive at every 6 meters(this is one mechanical module). So, this means around 45 motors with 45 VFDs. The guy told me it's good to create a separate CANopen network for the VFDs. So, this is the way he created the quote. We talked on the phone and I was told there is some limitation for the maximum devices to be addressed at the same time over a MODBUS network. It was something like 8. That's why we added some Ethernet device which handles the entire communication and I don't have to add communication logic(checks, error handling, etc) to my PLC logic. It converts the Modbus and is connected to the Ethernet port of the PLC. Everything is on the stage of QUOTE for now. Soon we will get notified about the customer's plans. That's for now. Penko
  5. Hello guys! I am in front of a big dilemma which way to go. We are currently writing a quote for a conveyor-like machine. It's transporters, which will carry out the transport between the warehouse and other parts of a factory. The transporters themselves are divided into modules - 1 meter each. Each module will have an asynchronious motor, controller by a variable-frequency drive, additional I/O(some pneumatics and sensors). If I have to hard-wire everything, there would be cables having length of 100 metres and above. Everyone knows this is not a good idea in some cases. Instead, I am thinking of developing a fieldbus, but as I don't have much experience with them, I am not sure what I need. Here is how I imagine the concept: - each mechanics module has an installed device on it where all the IO from the module is connected. So, 100 modules like this. Then, from the PLC, we connect all modules in a daisy-chain manner. The protocol is not so important - it could be Modbus, CAN(DeviceNet), Ethernet, whatever. My question is - what implementation would you use in this case? Are there such ready-to-use devices? If possible, I am looking for low-cost or average solutions in order to be able to prepare a competitive quote. Thank you in advance!
  6. Hello everybody! We constructed our own SCARA robot for internal company purposes. As for mechanics, everything is ready. However, we still have not decided how are we going to control the unit. The specifications are: axis X - 200 W, 0.64 Nm servo with brake, absolute encoder axis Y - 100 W, 0.32 Nm servo with brake, absolute encoder Servo drives(it can be 2-axis one or two separate ones) - Because it's a robot, there must be interpolation between the two axes. PLC or PC-based control over the two servo drives + some additional I/O. I asked for quotes from different well-known brands such as Beckhoff and Mitsubishi, but the price for control compared to the expenses for building the mechanics is several times higher. The problem derives from the amount of redundant features of the equipment. For example, we were offered a Motion Controller capable of controlling up to 16 axes and at the same time we need just two and so on. What we are looking for is a low-cost solution for controlling the unit. Because I do not have experience with some brands, that's why I am asking if anyone could suggest a brand manufacturer. It can be a manufacturer from anywhere in the world, well-known or not so popular. Thank you in advance!
  7. Hello everybody! I have configured I0.4 on my Twido as a High-priority event pointed to Subroutine 10. The purpose is: Rung 1 of SR10 -> LD I0.1 -> OUT Q0.2(but for 10 ms). If this was in the main program, I don't have troubles doing it. However, putting this in a subroutine does not make the trick. The way I am trying is with TP(Pulse) Timer, configured at 10 ms. So, the code inside the subroutine is like this. LD I0.1, TM1(TP, 10 ms) -> OUT Q0.2. Why do I need this? I have a machine vision sensor which is according to my mind very stupid. It does not have direct configuration of output duration. In my case, I need 8-10 ms and I need to control an air nozzle which orientates parts. Because of this camera's firmware limitation, I have to get the signal to the PLC and control the nozzle from there. In order this to happen as quickly as possible, I would not like to put the camera processing logic in the main program where it will be affected by scanning time which will additionally affect performance and it's possible that the duration of this how cycle is much more than the one expected. So, to summarize, the question is, is there a way to SET a coil from a Subroutine rung and this SET to have a specific duration. It's important to note that this logic is event-triggered and it will execute every time camera's READY signal has a raising-edge and the PLC detects the change. By default, the camera holds the output until the next trigger. This results in the parts being nozzled out before they actually reach the photosensor which triggers the camera. That's why I need to specifiy a certain output duration. Thanks
  8. Hello everybody! Here is what I am trying to find implementation for: By default, when writing to the Schneider Twido PLC, all memory variables are set to a value of 0. This is very awkward according to my mind because if you have a ready application which has some values it uses and suddenly the customer calls you and wants some modification of the PLC program - all values will be lost. If not something else, I would like to let the customer has the possibility to modify Timers via the HMI and this has to be done with %MW words, but they are lost after you upload a program at a future point? To summarize, is there a way to update the application, but do not touch %MW memory words and leave their values dependent on the execution, not to pre-configured values or 0?
  9. I would recommend Schneider(Telemechanique) Twido. It's a small PLC, robust, reliable and it has an easy-to-use software. You can have sections where you but several ladder rungs and call it for example "Lamps". Another one is "Initialization", etc. Thus, you order your ladder in a more understandable way.
  10. What software do you use for cyclograms?

    Thank you guys both about the comments! Peter, it's not a question only of motor-controlled devices(VFD, Servo, Step motors...). It's also a question of pneumatic-actuated devices and their action durations. @ssommers, what you have written generally resemblances our problems. Most devices in our machines are cylinder-driven and in most cases just a few are motor-controlled, so our case seems identical. Excel is what my father does, but there must be an easier way. Thanks once more! Penko
  11. Hello guys! As my problems are in a logical order, here comes the password issue. I took a look at the two types of protection - application protection and password protection. Yesterday customer's people came and took the machine. We are going to run the machine in, probably on Monday, at the town where the customer's factory is located. The PLC is a modular Twido. However, I did not manage to fully finish the operations. I only protected the PLC with a password, but there is another option(application protection) based on that I conclude it's insufficient. My goal is to fully protect the application, even no reads. Can anybody explain in short what do these two give me? Having in mind, I am willing to disable even reading, is it achievable with these two options? Also, having these two, if I eventually send the PLC program to the customer, will they be able to access it without troubles? Penko
  12. PLC Law

    Thanks! I printed them out and they are attached at the wall :).
  13. What software do you use for cyclograms?

    jstolaruk, I catch the main idea of your post. You solve the problem with programming. I was talking about, let's say you have a machine assembling some parts. There are certain movements(for example only discrete ones, pneumatic cylinders) and each of them takes some time. You additionally have timers where necessary or where the cylinder works without a sensor. Therefore, in order to create a cyclogram, what we do is to measure all times and try to put them in an excel spreadsheet so we can consider what can be improved(in most cases "timers" are the ones which can be lowered). Your suggestion is applicable when a HMI is available. In most of our assembly machines, where there is no need of HMI, we don't put one, therefore having such screens is not possible. Anyway, thank you for the suggestion and sure I will try it when having a machine requiring HMI. Penko
  14. Guys, I wonder something. Is there any suitable software for cyclograms? I mean, I want to add all durations in a machine and to see what is the machine cycle time. Of course, it must has to ability to support overlapping times. What is also should report is "dead times". I am calling "dead" the times where the machines makes nothing else than a certain action while time machine is waiting. I hope you got the main idea. By the way, what is there any other word for "cyclogram" in English? Penko
  15. electrical print making software

    @plcdp, I identify it as "Hope this helps" but it can be anything after all. I don't pretend to be right, I am not a native speaker of English.