suresh_

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Posts posted by suresh_


  1. hello Marco, clearly the manual is the reference N.1 however there is some learning curve and may be you need some guidance. As a start you need to know that AI Expansion Units  setting has to be done via available OUTPUT channels in your PLC, in the same manner input AI readings shall be done via available INPUT channels. This is the main difference compared with an AI embedded in your PLC. However in your case, I see another Expansion Unit directly attached to the PLC so it will consume its own IO Channels and you have to take it into account when you are programing your AI module. Speaking of Expansion module, please note that they are channel consumer,  AI/O or Boolean I/O cahnnel there is not difference, so if you have a module to the left of your AD42 keep in mind that this is consuming channels that you cannot made avaialble for other modules so you should study also this module manual. Finally, when you made your AI avaialble and converted into HEX you need to scale it in engineering units via SCL, SCL2 or APR. Experienced users prefer APR because is BCD free but is just matter or personal preference. Just in case, there is another similar issue in the forum so you may check it out.


  2. hello Benji, the basic concept is: once you set up your logic, you need to refresh it automatically every 365 days. First you have to set D0 that is control word for DT instruction and get rid of sec, min and hours. After that  you have to define your control logic and register it to PLC activating  W90.00 ( this can be done during commissioning or by the Client from HMI ) : clearly this has to be done automatically every 365 days. In the example given, today date is frezeed and MOV to D or (better) H register . To specify 365 days requirement  you may ADD #100 to D353 (meaning increment 1 Year =365 days ) and compare it with present date in the DT instruction. After 1 year from today date W0.00 will be ON triggering whatever actions you need. After your task is done W90.00 need to be refreshed again so the new date will be freezed for the next cycle. To check your logic you have to start simulation, go to Clock section in the Project workspace, manually increment the date by 1 year ( actually few seconds less) and see, after few seconds, if DT will set ON its output or not. If your logic is different you have to set up BCD data you need and MOV it to register, increment it by 1year and send to DT function as usual: DT function will  operate the timer accordingly. I hope it help.

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  3. hello Benji,I think you can easily fit this logic to your needs , however you have to decide if your customer should be allowed or not to adjust (or tapering...) Clock settings from HMI. Finally using H register instead of D can preserve your setting in case of persistent power failure. 

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  4. hello Muhammed,the ladder seems fine to me so it is tricky, however may be there is wiring issue or may be the PLC is confused about Expansion AI CH you effectively are using: i.e. if you are using only CIO3 you may try to inform the PLC about this fact like below: 

    MOV #800E 103 

    MOV #8000 104  

    You may also recall expansion error word  A436 and see if there is an error there

    I hope it helps

    immagine_2022-03-23_093257.png

     


  5. Hello Marco, based on AD041 I am familiar with, you may refer to attached screen shot. After that you may use SCL2 function (noting that numeric example in Omron  manual is wrong ) to scaling your AI ND consume it in your program logic.  Resolution is 6000 but full scale may change according to your input ( volt / mA) that has to be specified in PLC setting section. I hope it helps.

    immagine_2022-03-19_080434.png

    cp1w.jpg


  6. Hello Ben, you may use DT compare function e.g. is listed in the SS that is counting 365 days from today date but you may change it at your convenience. Once scheduled task is done you can refresh and start next cycle.

    immagine_2022-03-18_102113.png

    A.jpg

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  7. Dear Abdul, let me add another info for you. If you decide to use variables, you can use MOV to input a FP as you do for Integers. To do that you need to generate your Variable ( eg TEST) in the symbol section, specify REAL type and associate to a register (D100 eg). After that you can recall TEST variable in your ladder with MOV instruction and manually input your FP or associate it to an AI as you wish. In this way you can input your FP for later on use usingf MOV. According to PLC set up and register you selected ( HR, DR,..) , TEST variable may be or may be not saved once you switch OFF and ON your PLC. I hope this clarifies.  

    immagine_2022-03-11_083704.png

    MOV.jpg

    S3.jpg

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  8. Dear Abdul, as chelton pointed out, you may input a FP value directly and consume it on the spot if the consumer function allows a FP because not all functions do. Otherwise, when you write a FP value into a register to be manipulated later on, you cannot simply use MOV because MOV is not meant for FP assignment, so you have to find some turnaround to do this as I showed before. Otherwise you need to use ASCII string to FP that can be very tricky indeed. Bottom line, since OMRON is loose about data type ( bcs they are very concerned about backward compatibility ), there is no need to stress too much about data type, simply enter a FP and let the SW do the work for you.


  9. 10 hours ago, BobB said:

    I think I know where you are coming from. All numbers have to be converted to floating point before you can us them for floating point maths. Integers do not work. Use FLT or FLTL to do the conversion.

    OMRON PLC ladder programming is quite loose about variable declaration, so you can take an integer, convert to FP and manipulate it as required letting the SW to manage the variable type behind the scenes.

    SAMPLE02.jpg


  10. Quote

    The CPU of the PLC uses a 64bit RISC chip, multi-CPU parallel processing or time-sharing processing or task-sharing processing

    Quoted from OMRON NJ Sysmac Machine Automation Controller Principles and Applications 

    Personally I prefer reliability rather than state of the art tech, however I found quite impressing Execution time of LD (0.23 microsec) and MOV (1,76 microsec). Unfortunately PLC manufaturers are not so vocal about Floating Point Execution time (FLOPS) that is so crucial to manipulate analog signals. Now I don't want to compare PLC and PC but since Intel Atom is much slower if compared to Core iX e.g, I hope that introducing Atom to PLC will not lower the quality of PLC. Moreover, if manufaturers decide to cut costs on microprocessor quality, they could launch new HW configuration without providing customers any benchmark to compare with.


  11. hello pratik,  if I don't miss something, you have customary users sustaining a steady state flow plus random users that produce disturbance. as you have been told, firstly you should decide if min 55 psi is mandatory to have or not, if mandatory you need to keep your system reactive in order to cope with disturbance or change the piping design, otherwise you could smooth the feedback signal from PG 2 to provide some hysteresis and avoiding the pump runnning at full bore if not strictly required. Moreover you should know how your PID works and the mass of fluid in the line because this affects the reactivity of the system as well. 

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