PLCMentor.com

MrPLC Member
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Everything posted by PLCMentor.com

  1. software information

    Yeah but it actually has to be a product that my clients use.  At this point few of them use Siemens.
  2. software information

    We all dream about that software package that supports them all, but it just doesn't exist.  
  3. Wonder ware Intouch vs FactoryTalkview ME

    Actually I don't think its a fair comparison.  Wonderware is a SCADA system and Factory Talk ME is just an HMI.  If you want to compare then you should be looking at FT SE.  If you are looking at SCADA systems then I would also look at Inductive Automation's Ignition.  I think it beats them all.  I am not really a fan of the System Platform.  Wonderware used to be an easy system to get up to speed on and use.  You could literally open the box and just use it.  With System platform they over complicated it in my opinion.  
  4. Subroutine

    Are you trying to do an conditional JSR, i.e., you have logic to allow the JSR or inhibit it?  Rarely is that required and if its not require then don't do it.  Most PLC programmers I know in the SLC use JSR's for program organization.  Then use the logic in the routine itself to handle any conditions for outputs to be on or not.  Keep in mind that if the routine is not scanned then the outputs will be left in their last state.  Finally how did you place that latch.  If you branched around the return then the routine will return without operating the latch.  just put the latch on a rung before the return.  Also you really don't need the return. 
  5. Add pause botton Allen bradly SLC5/03

    Well first if it's a safety issue then the machine should be shut off.  I understand that this is a class but generally I do not like software (that can be changed by anyone with access) dictating the safety of my operator.   That said, here is my 2 cents.  First you really are not worried about keeping your inputs in a certain state but I can see where your outputs might be important.  You will have a sequence for the palletizer. All your pause button will do is stop that sequence from moving to the next step.  In a little more detail, your palletizer will have several sequenced steps that will each operate outputs.  After some expected action, it will move on to the next sequence step.  Your pause logic will just keep it from moving on to the next step.  You don't need a temporary end statement.  
  6. Managed Switches

    I have seen people go overboard with managed switches but I generally have one on each significant system I install.  The biggest networking problems I have ever had seem to be with drive systems.  They usually handle a lesser number of packets so swamping the network takes them out first.  Your system is pretty small, but the cost of a managed switch is pretty small compared to the cost of the freaky problems that can occur without one.  When you have a problem with a network it can be very time consuming (ie, downtime).  Time is always expensive. 
  7. New to PLC's

    Ok so I might be biased but I don't like the canned 4-5 day courses.  They work well for some I guess but more often than not they try to cram a lot in and you remember about half.  Many of the college courses are taught by professors that learned out of a book.  That is getting better and many community colleges have pretty good programs.  We started the PLCMentor.com website because our clients had a hard time finding quality training that met their techs schedules.  Taking the tech out of the plant for a week has problems all of its own.  We offer self paced training with a few very important extras: 1.  We have self paced training and video libraries but the focus is on learning to program.  Not hand holding but scratch your head and work your way through it programming.  We will nudge but not lead you step by step through it. 2.  We offer the ability to send in your class programs and have them reviewed by experienced professionals.  Not just does it work, but would I want one of my engineers to install it at a client site? 3.  We offer a weekly question and answer session where just about anything controls oriented can be discussed.  I have had people bring their programs to discuss problems they are having and to get help with difficult logic.  I have had new programmers just trying to figure out the basics.  The only rule is that the instructor has to be competent enough in the subject to discuss it.  The classes are recorded and we have around 100 hours of past classes on many different subjects.  Sometimes its nice just to see there are people out there that know less than you!  The only drawback I ever see is that the student has to be self motivated.  Nobody is going to be watching to see if you participate or even try.    Oh and I forgot your additional question.  RSlogix500 is used to program SLC500 and micrologix PLCs.  RSLogix5000 is for the ControlLogix and CompactLogix platforms. 
  8. Bit Shift Left BSL

    I made a vid on this a while back.  It's usually in our paid content, but I moved it to the sample videos for you.  Hope it helps: http://www.plcmentor.com/Training-Videos/PLC-Training-Videos/Allen-Bradley-Rockwell-Automaton/RSLogix-500/RSLogix-500-Instruction-Set-Videos.aspx Or you can just go to the site and follow menu:  PLC training videos/RSLogix 500 instruction set You will have to register on the site to login but the BSR/BSL video will be in the sample video listing.  
  9. AB SoftLogix

    Well you hit upon another of my dislikes - Labview.  But that's more of a personal preference.  I suspect you will still need some sort of OPC server to talk with softlogix also even with them both on the same PC.  This is just conjecture, but softlogix attempts to look like PLC hardware and uses standard methods of communication, ie some sort of OPC server.
  10. Alarm and Event Banner don´t show in Runtime

    Well I cant really help but I had to say I like your screen!  You may need to give more info about how your tag server is handled and how you handled redundancy.
  11. AB SoftLogix

    In most instances I would just say no.  There are some PC hardware setups that are fairly similar to the robustness of a PLC; however, when you compare costs I suspect the PLC will be cheaper.  The windows operating system does not really have the reputation for solid 24/7 operation unless maybe you go to one of their server packages.  Also ladder is not chosen because of its mission critical capabilities but due to its (supposed) familiarity for maintenance personnel.  I would ask yourself this.  Will it matter if I have to reboot my control system periodically?  If not then PC control may work for you.  I dont have any installations where this would be acceptable.
  12. Request help of the following counter example

    Ahgggk!  You are correct!  I dont know where my brain was with seeing C5:1 going to 0.  It will increment up and down with C5:0. 
  13. Request help of the following counter example

    This has to be a school project.  Nobody in industry would really want a system to operate like this and nobody would call it a GO switch. There are several things wrong before we even get started. 1. It looks like the author assumed a reset would set the accumulator to 1 instead of 0. 2.  Have to assume the stop PB is a normally closed contact and the go PB is a normally open - pretty normal but should be spelled out. Also I am assuming this is an AB processor due to the counter addresses. 3.  Assuming that the counter did reset to 1 then the program will still not work as required.  The first press should increment counter c5:0 and set the done bit which will in turn activate the counter down logic in the last rung.  This will change the accumulator value of both counters interestingly making C5:1 a 0.  The next press of the Go will not cause the motor to stop as the accumulator will be a -1 at that point.  Decrementing the accumulator for C5:0 will cause the done bit to reset. 4.  Even if C5:1 could get a done bit from this logic, the next rung would reset it when it went to done. Thus the motor rung on the first rung would never see that done bit.  5.  The plus is that the stop pushbutton would stop the motor and the go button would start it.
  14. SLC500 to Compactlogix Migration

    There is another thing to take into account with this also.  Are the existing controllers on four separate independent machines?  If so then I would leave them on separate processors.  If they are controlling different parts of a combined line or machine then combining them makes sense.  The question you want to ask is, "Could I take this down and not affect the others?"  If so then keep it on a separate processor.  Maintenance, upgrades, etc will be made easier.  If taking down one processor requires all the others to be out of service anyway then combining makes sense.
  15. Will MVM work for this

    I would also ask if there is a reason they have to mask it.  Are the other bits used for other purposes?  If not a simple move should work and be easier on the next guy.  More obvious anyway. 
  16. LOGO! Soft Comfort on ML1400.

    I guess anything is possible, but I highly doubt your AB PLC was programmed with Siemens software. Your Logo software was probably used on a LOGO PLC in your plant.  Your initial idea of grabbing the program with RSLogix500 was correct.  The two manufacturers are very particular about that.  Keep in mind that any program you pull off of a ML1400 is going to come without descriptions or other documentation.  All of that information is stored in the RSLogix500 project and is not loaded to the PLC.  You will grab the program just not anything that describes I/O, registers, or other comments.  What you get will work as a backup, but it will be extremely hard to look at and understand.
  17. Current limit on PLC 5000

    I see that nobody has commented on this so I will shoot.  First I have not experienced this with the 5000 series controllers.  I did experience this on one of my first projects that involved a PLC5 rack with lots of analog I/O.  The PLC5 supplied its analog outputs via the rack power supply and I had too many cards in the rack for the power supply specified.  Not a pleasant moment!  Second I am curious about the "standard" 250 ohm resistor.  I assume from the text that the resistor is in series with the device.  All of the transmitters and other loop powered devices that I have used have sufficient load built into the device to not require an external resistor.  Of course having too much resistance on the loop will cause problems as will adding to many devices on to the loop (ie, adding too much resistance).  I do agree that the resistor is not necessary with modern output modules or (I will add) field devices. 
  18. Creating Custom Graphics for PVP Project

    I am not a fan of overly fancy pics on control screens.  Many times the important information gets lost in the beautiful picture.  In addition imported images if too large can slow down some systems.  Simple is usually best but also making sure the information is conveyed in an easy to understand fashion is also important.  Since a lot of our development is around process control, we use the P&ID diagram as our "template."  Not an imported template but as a go by for our screen development.  The screens are developed using whatever built in graphical capabilities the software we are using provides.  Now days the available graphics are similar - especially since many HMI/SCADA systems include Symbol Factory.  I actually feel that some of Symbol Factory's valves and pumps are too busy and are counter productive to the information I am trying to convey.  I generally create a simpler object that shows the information I am trying to convey (run status, fault status, etc).  I agree that boxes are not the best looking interface design, but just be careful that you do not make things harder on the operators.  Here is a youtube vid that I created a while back for our batching system; however, you can see some of the principles that I mention i the video also.  https://www.youtube.com/watch?v=uJtTiEKFGWQ&t=2s
  19. Bets practice: IO in local 1756 chassis?

    That's somewhat a loaded question.  Practically that depends on the project.  I agree that giving preference to such modules in your design is a good best practice; however, deciding which modules to put where depends on what you need for your situation.  We don't do a lot of motion control so I cant speak to that.  We do have a variety of communication modules, but that is highly dependent on the project.  I would make sure my comms modules get priority for being located in the main chassis.  I also would allow for expansion and growth of such modules in the future.  Then practicality kicks in. For example, often our main PLC is located close or in the MCC room.  That makes it highly efficient to locate the I/O modules associated with motor control in that chassis.  Often of our other I/O is spread about the process and remote cabinets are used for that.  I'm sure Rockwell doesn't really like my preference for Flex modules over point I/O, but the stupid way they arranged the wiring on those makes them an electricians nightmare (and thus mine also).  I guess to sum it up:  best practices as you mention are great, but each project must be evaluated within its own criteria to make sure the best practices are "best" for it. 
  20. Rslogix 5000 school project help

    My first thought was that deleting the Main routine and inserting a new one may have messed something up.  I tried it on a new program (deleted the main routine and inserted another) and it still set the new routine as the main routine.  I still think this is your best bet.  You should be able to just look at it and tell.  If it does not have a little 1 marking it then it is not set properly.  I'd bet my last post that this is the problem.  See how confident I am?
  21. Rslogix 5000 school project help

    Bravo again Michael!  We all get those blinders - especially with the client over your shoulder or at 3am. Here are some items to look at: 1.  Have you defined a main routine in your task properties? 2.  If you are using more than one routine, is their a JSR to the other routines from the main routine?
  22. Rslogix 5000 school project help

    Michael!  LOL I would also be a rich man! Online and calling the routine (JSR in Allen Bradley)  have both been mentioned and the fact that you can toggle your output and dont have to force it on/off indicates that your logic is not being scanned.  Also - you didnt use the same address on two outputs did you?  Big no-no!  Last one wins...
  23. MicroLogix 1000 Communication Problems

    Flashing fault LED indicates major fault.  Odd to see that for the first time with a older program.  If it is faulted then the program is not running and the outputs will be (most likely) off.  Serial programming with a USB cable can be fun.  Some just don't work.  I would suspect that since that cable is made for the PLC then it should work, but... maybe not.  I would try going into your window devices and see what comm port that device has grabbed.  That is really the only thing you have to setup manually with the auto config.  I will automatically and reliably go through all of your baud, error checking, etc settings.  The comm port does need to be correct.  You will need RSLogix500 to see the program and reset the error, but with a 1000 you should be able to get the micro lite version and do what you need to do.  There is a link to it on this site. 
  24. Communicating with CompactLogix L32E

    I must be missing something.  Is the processor you are trying to connect to not connected via DF1 and Ethernet I/P?  named MonoFloBoxSnap... IP address 192.168.2.10
  25. Communicating with CompactLogix L32E

    Excellent point Joe!  You did mention downloading over the existing application anyway but if this is a working system, it is always best to upload and have the latest revision saved.  You may think you have the latest revision, but good practice is to make sure.  If this is a new PLC and you just want to dump your program into it and dont care about the existing program then a firmware change is ok.  Your local rep or a local integrator can help you upload the existing program if you cant get it on your PC.  Also they might be helpful for your first firmware upgrade.