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Posts posted by Emil

  1. Hi to all!

    M91, as it is, cannot be connected direct ot Ethernet. The same is for V120. You can try ot use any serial to Ethernet converter, but my feeling is thhat it will be more expensive than the PLC itself.

    Important note - now Jazz 2 has Ethernet adds-on module MJ20-ET1. With it, you can "see" the controller via U90Ladder and other Unitronics software tools or to communicate Modbus IP.

  2. Two notes:

    1. "Limitation" CANNOT be metioned in any documentation, as it depends on many factors. This number comes from limitation in communication between PLC and EX-A2X. As Yair stated in his post above, in bottom line of Hardware configuraiton window (VisiLogic) there is a "calculator" of communication load. Any one can check before starting to build his project.

    2. In fact, there is no such limitation! You can add Remote adapters EX-RC1. To each adaprer you can connect, let's say 6 x IO-ATC8 = 48 universal 14 bit AI. You can connect up to 60 x EX-RC1 to one PLC. This means - 60 x 48 (via RC1) + 48 (on A2X). In my calculator the number is 2928. You can add another few analog I/O on board or Snap In module, but this will not change the final situaiton drastically.

    BTW - having 6 x ATC8/AI8 ot each adapter, you can still add up to 2 more I/O modules with digital I/O...

  3. SB80 is like a switch to perform the calculations. You need to SET it with one scan condition each time you need ot perform the linearization math. Before SET it, you need ot take care to store X value in SI84 and next net after SET SB80 - to store tghe result from SI85 to any MI. If Linearization points X1, X2, Y1 and Y2 are the same for both (or more) Linearizations, you can store relevant values in SI80-83 with Power up condition. If not, you need ot make the "snake" net before each calculation.

  4. Copy memory and Struct are different functions. You define the thhings in different way and, according to the definition, you can receive different results.

    Can you send mail ot support@unitronics.com with some example what exactly you did? In my understanding, Copy Memory needs ot be the simplest way ot acheive your goal. I want to see how you define both modulles and why you get different results.

  5. No. On GPRS you have only one communication channel. Theoretically, you can switch between Modbus and PCOM once established GPRS connection. But this means that you will have only part time connection between SCADA and PLC and it will be difficult to synchronize between controllers themselfs.

    Idea - use cellular router instead GPRS modem. It will let you to open 4 communication channels. While one port will be opened for the SCADA, with other ports you can communicate Modbus Master Slave or even better TCP or UDP Raw.

    If you are interested in such solution, I can give you some more info.

  6. Hi,

    First - Modbus is communication protocol. The question "Which cable to use with Modbus" seems to me like "Which kind of fuel to fill in my horse?"

    Let's assume Modbus is running on RS485. In this case the question needs to be "Which cable to use for RS485"

    ... and the answer is:

    Shielded twisted pair with impedance between 100 and 120 ohms.

    Some producers offer special cables for RS485, which, of course is the best.

    Some recommended cables in attachment.


    RS485 recommended cables.bmp

  7. You can define up to 6 numbers in SMS phone book. One (and only one) of them can be defined as Indirect.

    When you define a mesaage to send, when you click on "S" column to define the bit to send, U90Ladder opens Phone book and you can "Check" in left column the phone numbers you want specified SMS to be sent.

    a) If you check only +1234... it will send only ot it.

    B) If you check only te indirect number, it will send only to it. BTW - you can make relativelly simple Laddewr logic to fill different numberts in stated MI addresses and this wasy to send to many numbers.

    c) to both - if you will check both +123... and the indirect number.

    d) to neighter of those numbers, if you will not "check" any of them.

    I hope this answers the question.

  8. Hi Aus,

    Definitelly - you can use V230 without Snap In module!

    You can use it without any I/O at all - just as inteligent HMI, communication center and/or Data Logger.

    You can add to it Snap In module only.

    You can connect Expansion modules only - without Snap In.

    You can connect and use both - Snap In AND Exapnsion modules.

    All these options are fully legal and it's a matter of project needs and ... personal preferences!

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