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Posts posted by Damian

  1. A bit of a weird situation with the unit in title.  It is installed and working as you would expect (new application, just programmed this week), but I noticed some odd noises coming from it.  I disconnected all the connectors and cables except for the 24VDC supply and it still makes the noise.  When I cycle power to it, it is quiet up until it completely finished booting and then runs the application.  As soon as the application starts running, the unit starts making the crackle sound again.  There are not any relay IO, so it can't be a chattering contact.  It is hard to tell if it is the speaker or something else.  Attached are a couple videos where hopefully you can hear the audio OK.  Any ideas on what it might be?

  2. MI2 & MI3 should be able to range from 1 to 240, with MI2 being less than MI3.

    The question was, what do YOU have them set to?

    Anyhow ........

    MI0 is your encoder count. All MI have a range of -32768 to +32767.

    That means the largest value you can measure in MI0 is 32767.

    In your code you multiply that by 0.00293

    So, 0.00293 * 32767 = 96.00731

    Once it passes 32767 it will jump to -32768, so you immediately jump to negative numbers. So it is NOT counting back down. It is infact counting back up from -96.

    You need to set the encoder rollover point and then either have it automatically reset, or use the marker pulse on the encoder to reset it.

    You then need to keep track of the rollover times separately.

    For example, if you have a 1000 line encoder you will get 4000 counts/rev. Set it to roll over at 4000. Everytime it goes from 4000 to 0, increment an MI or ML integer. Your total distance will now be that integer + the fraction that remains on the encoder.

    Also, a word of caution. You have your screen set up for 9 decimal places. The floating point arithmetic in the PLC is not anywhere near that precise.

  3. Just to put some numbers to this to give the OP a sense of timing.

    Using a V570 (fastest CPU) and dedicating connections to a single slave each, I can perform a full read and write cycle to 4 slaves in on average 15ms. That is, I can read and write to all four slaves in under 12.5 to 20ms.

    It peaks out at 20ms and occasionally I might get one 22.5ms cycle hear or there. Not deterministic of course.

    Now as an example, and I decide to multiplex one socket and talk to all four slaves that way you will find that it takes about 100ms to establish the connection. And this is for each slave. Once you are connected you will want to do a read and a write before opening the socket again. Between that and the socket close that adds about another 15ms of overhead.

    So all together you will end up around 450ms for a read write cycle to all slaves by multiplexing. So multiplexing in this example is slower by a factor of about 20 times!

    So, be careful doing it that way. Most of my processess cannot handle that degree of latency.

    They have developed FAST socket Open/Close FBs that are much faster, but they have not officially released them yet.

    It is also possible to create a socket pinwheel, although the code gets quite complex. The theory behind it is you use three sockets or so. While you are talking to slave 1 with Socket 1, you start connecting to Slave 2 with Socket 2, then maybe slave 3 with socket 3, once Slave 1 is finished Socket 1 closes with Slave 1 and then connects with Slave 4 while you're still reading from Slave 2 on the other socket. Then Socket 2 closes and connects to slave 5. Etc. You get the picture. It helps mitigate the time wasted establishing the connection.

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  4. Hi Emil,

    You have nothing to appologize for. I like the fact that your direct and blunt and not afraid to speak your mind. I enjoy this forum, and you have played a key role in making it what it is. I think of it almost as a "Hitchhikers Guide to the Unitronics". I very rarely run into a problem that I have to ask for help with, and this is because more often than not the answers lie somewhere here in this or the old forum. You are an asset to the company. Please don't ever feel you need to choose your word's carefully with me.

    I tend to forget that the EX-A2X exists. Looking back at what you wrote, it was very clear you were talking about this, so the mis-understanding was all on my end. So for that I offer you my appology.

    I understand the position Unitronics has taken regarding not publishing the specs on the cable. I don't agree with it but I do understand. Based on my experience, people are going to do it anyway. So you are better to give them the info and better their chances of getting it right as opposed to "winging it". You will never be able to stop customers from doing "dumb" things. Your only recourse I think is to keep things as simple and make things as robust as possible while still fitting into the economic framework your targetting.

    Keep up the good work!


  5. Hi Damian,

    The quality of the cable between the controller and EX-A2X or XL modules-adapters is very important for the stable, drop-free connection. It's quite not so simple as you says.

    Please - if you don't want to follow the right instructions and take the full responsability for any further problems you will have - it's up to you. But - please - don't teach the other to make wrong things! Then they can understand you wrong, have problems and will come with the problems to me, not to you! And I really don't want anyone to have problems with Unitronics stuff - never mind who is guilty. So - please again - let's follow the rules!

    Hi Emil,

    I sympathize with you when it comes to people coming to you with their problems. I started out in tech support, and as an integrator that role never really vanishes. The vast majority of the time it was quite simply the customer's fault and rarely a legitimate issue with the equipment. Either they didn't read the documentation, didn't follow instructions, or simply were not qualified to be doing what they were doing.

    However ...... if everything went perfect and nobody ever did anything wrong......... If customers didn't need help, then your job, as it exists right now, would not exist. It is a common for me to hear maintenance personnel from various companies I visit complain when a machine breaks. It makes me wonder why they think they were hired in the first place.

    I do take exception to the assertion that what I have said, and the cables that I have made for myself are "wrong" or are somehow lacking in quality. On what basis do you make this claim? You haven't had to field any calls from me on this, and you haven't seen what I have made. If you would like, substitute the word "right" with "recommended". I have not used the newer EX-A2X expansion module yet. Perhaps the cable for that is "fancier" than the simple shielded cat5e cable that came with EX-A1. I don't know, so I can't speak to it.

    To a larger degree, I think it is worth asking the question of "why are we making a simple expansion IO module that requires a fancy cable to work properly in the first place". I look at all the other technology we utilize (Profibus, Ethernet, CAN, etc.) Why wasn't the expansion comms done with something more inherently robust? I use other bus systems that are just as fast as the expansion comms that utilize simple un-shielded twisted pair wire. I think there is something fundamentally wrong with the idea of designing something involving communication to a remotely mounted device that doesn't allow you to "cut to length" the cable that you need. From a practical standpoint, when we are first designing systems and ordering material, we rarely know beforehand exactly how long cables will need to be. So by your recommendation, I always have to choose between possibly ordering a cable that is too short, or possibly one that is too long so that I have to find a place to "hide" the excess loop of cable. Or as a third option, I can wait until after the system is built, and then put everything on hold for a few weeks while Unitronics is making my custom length cable.

    I have also not instructed or taught others to do anything wrong. Everyone else can make their own decisions on what their capabilities are and what they feel comfortable doing. For this application, I would not recommend an expansion cable of any kind, no matter who made it. They are better off using CAN at that distance. The key to minimizing calls to support and trouble with the product is to provide the customer with the tools necessary to do things properly. Rather than insisting on making everyone’s cables for them, it would be far better to post a drawing in your documentation library that instructs people on how to do it themselves properly.


  6. Good suggestion, Damian. Or you could use an EX-RC1 and make the I/O a remote drop. The V1040 has a CANbus port. Either way, it will make a more stable installation.

    Getting a super-long expansion cable made by the factory is going take a few weeks.

    Joe T.

    Hi Joe,

    I agree. If you need a lot of IO at that location, the EX-RC1 makes good sense. If you only need a handful of IO it can sometimes be more cost effective going with the likes of a V120-22-RC6, which is cheaper than getting a EX-RC1 and an IO-DI8-R08 for practically the same IO. Then you get a Bonus screen to boot for displaying status or maybe as a remote HMI as well as bonus comm ports. The fact that the EX_RC1 isn't battery backed might also sway that decision.

    Not certain why Emil is adamant about using a Unitronics made expansion cable. At the end of the day it is just shielded CAT5e. If you purchase good quality shielded connectors and know how to make an Ethernet cable this is about as easy as it gets. You just have to make sure and maintain the correct twisted pair relationship and extend the shield wire out for termination at one end. I always make my own expansion cables just so that I can make them exact length. I have never had an issue with a hoe grown cable.


  7. I have a vision 1040 and I want to locate my expansioin modules 75 feet away

    using a good belden/twisted pair/shielded cable. I have been told that distance

    will be pushing the limit.


    Food for thought,

    You could get another small Uni with CAN and go UniCan between that and the V1040. then use a short expansion cable to you remote I/O, or, if there is enough, jsut use the I/O on the Uni.

    In this way you could use the Uni as a passthtough with the fringe benefit of having a remote HMI.


  8. Hi.

    I'm having trouble with the compare funktion. When in online test mode I can see that the statement is true, the block is red but it will not set the coil behind it.

    I've had this problem before but it have been solved by downloading the program again. This time it dosen't fix it.

    I'm using vision130 with unitronics V 8.6.1 .

    Anyone having any thoughts about this?



    Have you done a cross reference to check if you accidently created a duplicate coil elsewhere?

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