Duffanator
MrPLC Member-
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Posts posted by Duffanator
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Handshaking is a process in where a computer and another peripheral device establish "rules" for communiciating with eachother. Like what baud rate to use, parity, and protocols. It is most commonly used with modems (When a modem picks up and you hear all the squealing that is actually a handshaking process taking place to determine what communication settings the two modems are going to use to communicate with eachother). -
Wow, wouldn't that be fun if you could only use an instruction once in a program? I pull my hair out enough as it is -
Yes. A lot of our European machines come with spring clamp terminals and they do wear out. Especially on safety circuits where you have to remove wires for troubleshooting they do not hold up well at all. The springs wear out or bend and then they don't hold the wire correctly and you can pull it out. Also, in our environment they tend to rust and break because of all of the humidity in the air. We use stainless steel screw and clamp terminal blocks just for that reason. Vibration isn't so much of a problem for us though, so I can' speak to that but as far as holding up in harsh environments and repeated use they don't seem to work well at all. They are nice in the right situation though, it's much easier to put wires into them than a screw terminal. We shy away from them though just because they don't hold up. We usually end up changing them out anyway so we just put the stainless steel screw terminals in right off the bat. -
I've been looking into that solution as well. I've had Mitsubishi come in to demonstrate the MES Interface IT module and their software solution and that looks great. The problem is that my managment wants to do something with the equipment that is already there (basicly they don't want to spend any money) so I am trying to come up with a solution that will work. I've already tried to explain how it won't do what they want as good as a product that is made for that purpose, but no one listens. Trust me, no one is more upset about it than me and I'm sure more than a few of you know how I feel. Inntele, thank you for the pictures. I'm going through them now to see what I can do with that. If anyone else has any suggestions I'm all ears! Thanks for the help! -
yeah, that would be fine. You can e-mail them to me if you'd like. dkeller@hqm.com Thanks a lot! -
Hey all, I am trying to make a downtime tracking system with a A2SH PLC (that's what's already there) and I was wondering if anyone had a better way of doing this: I want to be able to store a maximum number of about 30 events that would have a time stamp and error code associated with it (like line stopped due to e-stop being pressed or something like that) and it would record this data into a slot and the next time an event occured it would go to the next empty slot. I will also be pulling that info out periodicly with Citect so I will have to tell Citect what slots are "full" and then tell the PLC that those slots have been "emptied" by Citect reading out the data. I can do this will long rungs of code with a bunch of M contacts that represent each "slot" but that would be huge, does anyone have another idea of how to do this that would be a little less tedious or use less steps in the program? The program in the PLC is a little over 2K steps and the maximum size is 14K (I think) so I have the room but I'd like to keep it as simple as possible. Thanks in advance for the ideas! -
Ahhh, well the motor windings are wound in a way that creates magnetic fields that "push" the rotor inside of the motor around in a circle. If you measure resistance of a motor from phase to phase it is typicly very low. The only thing that keeps the phases from shorting together is the inductive reactance that the magnetic fields create. I think, I'm not 100% sure about this (Paul would probably know better), that when the rotor is slowed due to load on the the motor that reactance value changes and basicly lowers the "resistance" of the motor. So, since the effective resistance lowers then the current will go up. It all has to do with the magnetic fields created by the motor windings and how those magnetic fields interact with the rotor. EDIT: Also, motors are designed to run a specific frequency, in the US it's 60 HZ and in Europe it's 50 HZ, when you run a motor off of an inverter and lower the frequency you will also notice that the current will increase without any additional load on the motor. That's because the magnetic fields are becoming more "static" the less they change. If you put a DC voltage on a motor it would draw very high amps because it would effectivly become a short circuit because there are no magnetic fields being created to limit the current. The lower in frequency you go (away from the native frequency of the motor) the less Inductive reactance you are creating in the motor and it will have the same effect as applying more load at 60 HZ. If you increase the frequency past 60 HZ the current will actually go down a little bit because you're creating more reactance, i.e. the magnetic fields are being created and collapsing at a greater rate. -
Yeah, that is correct. The more load you put on a motor the more work needs to be done, the more you need to increase the Power to do that work. Since P=IxE (or power equals current times voltage) you need to increase something on the other side of the equation to make it true. If P goes up then either I (current) or E (Voltage) needs to increase as well. Usually you can't increase the voltage so the only thing that fluctuates will be the current. And like what was stated before motors are only rated for a certain horsepower, which really means a certain voltage/current combination. You can run a motor at 240 volts with an amp draw of 2 amps and then run the same motor at 480 volts and it will draw somewhere close to an amp (provided you can wire it for different voltages of course :-P) and it will still be the same amount of Power, HP in this case. -
I don't think that's true. You can cut the power to the SSR with a contactor if you wanted to but as long as the SSR was fused or you put a circuit breaker (like an ABB or something) in line with it, it should be ok. I do put contactors inline just for a second line of defense if I had to cut the power in case of a runaway heating plate but I don't think you HAVE to do that unless there was a safety issue. If you are working on the machine then there needs to be a disconnect that would cut all power to the machine. -
You can turn only one side off, but it's not recomended. I've had instances where the other side of a heating element shorted to ground and the heating element would heat continuously because it was not being controlled with both phases. Also, both sides need to be fused. Not just the side you are controlling. I would recommend getting a good 3-phase SSR and only using two of the phases. Continental makes a really good 3-phase solid state relay that I've used on several machines for heating both 3-phase and 2-phase heating plates. http://www.eurothermonline.com/product/RVD3-6V75TH Just use L1 and L3 for two phase heaters and you will be good. And they are dinrail mountable. I've had whole heating plates short to ground and not take out these SSR's, they hold up very well. -
Mitsubishi came in yesterday to go over the MES InterfaceIT module and it does look awesome. They are coming back later to set up a test database and connect to one of our machines to do a live demo of it. I will make an update after that but from what I've seen already it looks like a very good solution. I was very impressed with it. -
We use the Brady IDPal handheld labeler with vinyl labels. They seem to hold up the best in our environment where everything, eventually, will get wet. It's slower because you can only do one label at a time but they hold up really well. -
Has anyone done an upgrade from Windows Vista to Windows 7 yet? I had recently bought a new computer and it came with a free upgrade to Windows 7 when it comes out later this month. I'm just wondering if anyone has had any experiences (good or bad) with doing the upgrade. The computer in question has Vista premium 64 bit. I know at least one of you Techno-freaks has done this already! -
Jeez, that's awesome! I wonder how many of those color gears the destroyed programing that thing :-P -
The last time our Mitsubishi rep was in and we were talking with him he said Allen-Bradley has somewhere between 90-95% of the market share in the US. That doesn't suprise me, Allen-Bradley is everywhere. I don't know why though, I think there are much better solutions out there than Allen-Bradley but that's just my personal opinion. He did, however, say that Mitsubishi is doing a much better job of marketing in the US now. There are two car plants, I think Honda and Toyota, in the US that are 100% Mitsubishi driven and I think GM is looking into building plants with Mitsubishi control as well. Our plant is food production (pork products) and we have always used Mitsubishi, but any new equipment that comes in is either Allen-Bradley, Siemens or Mitsubishi control. I would think it goes in that order as far as popularity, in the food industry anyway. We never see Omron, GE, Idec or any other brand of PLC in any equipment we buy. -
Yeah, I know. I don't trust them for that either. I feed the main power through a contactor to cut off the power to the heaters then from there I distribute it to fuses to protect each heater and then through the solid state relays. So both the contactor and the SSR's will shut off. Next thing you know they will want the machine to keep running if you hit an e-stop because they are loosing production! -
Hey all, I recently rebuilt a rollpack packaging machine for one of our plants and one of the changes I made to it was to cut the power to the heating plates (there are 4 heating plates that are fed 480 volts to heat) whenever a safety is not made. I do this two ways, one is hardwired through contactors and the other is software, I stop firing the SSR's that feed the heating plates. All of our new machines do this so I'm assuming it's some kind of standard since you can access the heating plates once the safety covers are removed and there could possibly be 480 volts there. Well, they don't like it. They claim that they are loosing a lot of production time waiting for the heating heads to heat back up (why are they pulling safeties off that much and why for that long? I don't know, I already asked that question). They want me to change it back to the way it was but that would involve a major rewire of the machine controls as well as program changes. Not to mention that it's unsafe, potentally exposing maintenance and production to 480 volts. Are there written codes or anything for this? I could not find any but I'm also not sure where to look. I'd love to show them codes and say too bad, live with it since it's probably their fault they are loosing production time. Especially since I did the rebuild, I don't need someone getting lit up and then it coming back on me. Any information would be much appreciated! Thank you! -
Yes, thank you Paul. The amount of knowledge you have is overwhelming. I will have to look over this information more in depth when I get time. I'm interested in learning more about this since our company has started doing studies on it. I have too many things I'm trying to learn about and not enough time! :-P -
This is a little off topic, but what determines what arc flash rating a panel or switchgear is? Is there some kind of formula that you can use to determine this or is it just a set of arbitrary rules that determine it? -
Tell me about it, We're still on version 5.5 and they refuse to spend money to upgrade it or send us for training. Our Citect system is going to die because there are only 2 of us that know anything about it and no one wants to learn or spend money on it. It's such a shame because there is so much it can do and no one realizes it. -
Hey kaare_t, Have you yourself used one of these modules? The more I read about it the more confused I get. I was assuming that you would just have one of these modules in a central location somewhere and it would be able to connect to multiple PLC and gather whatever information I want it to (if you have the correct licenses that is). But in the paperwork for the CPU (Q12DCCPU) it says that it can't connect directly to other PLC CPU's through ethernet, only CC-link or serial. I can't believe that is the case, that wouldn't make any sense at all. You don't need a module at every PLC do you? That would be rediculous. I'm having our local Mitsubishi Rep come in and explain what this thing can do but he can't come until the 12th of October and I kind of want to get an idea of what I'm going to use before then. Thanks! -
I looked into that stuff and the other thread and it sounds like it's something I could use. Everything I've read so far though only shows being able to communicate with Q-series PLCs though. I thought I read in another post that with the MESInterface IT module that it had Rockwell drivers for talking with AB PLC's and also had the ability to communicate with other Mitsubishi PLC's such as A-series. This would be ideal since some of our equipment has A-series, FX PLCS as well as Allen Bradley SLC 500 and Control Logix processors. If that module could do all of that then I'm definatly going to try that out. But none of the information I find on the MEAU site indicates that this is possible. What's the deal? -
Hey all, We are going to be setting up a downtime tracking system at our plant soon and since we have mostly Mitsubishi PLC's it would make sense (maybe) to use other Mitsubishi products for this as well. Has anyone had any experience (good or bad) with any of Mitsubishi's "F@catory floor" stuff? Like OPC servers and their data collection systems? What are their pluses or minuses? What all can they do as far as data collection and downtime tracking? -
Hey all, I am looking for some general information about OPC and what it can do. We are looking into putting in a OEE (Overall Equipment Effeciency) system in our plant and we have been looking at some vendors for it but it was determined that we would also like to look into doing something in house as an option. Basicly we want to track why a machine was down and for how long. I've never done anything with tracking this kind of information to the level they want to do it and I'm not sure how to go about it. I've heard a lot of things about OPC applications, software and servers but I don't know a thing about it so I was wondering if someone could give me a kind of intro into it just so I know what I'm dealing with here. Here's the things I really want to know.... 1) What exactly is OPC? 2) In what ways can you interface with it? 3) Does it create reports or is that a seperate software application that data needs to be exported to? 4) Are there limitations to what you can use to connect to it (like brand of PLC and such) Sorry if I'm way off base and these questions don't make sense, I'm just trying to better understand what this stuff is all about. I appreciated any info, thanks!
Inductive Switch
in Mitsubishi
Posted