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TConnolly

--|| |-- WTH is this? Is it some kind of differentiated contact...

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What does this symbol in my ladder indicate? Is it some kind of differentiated contact or something else? I looked in help and only saw that a differentiated up instruction is preceeded by an @ and a differentiated down is a %, and an immedite refresh is a !. I looked at the IL and didn't see any of these before the instructions, just basic LD and OR instructions. Thanks. "Still groping my way around the Omron world" Alaric.

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Pretty sure that means that the bit that it is referring to is evaluated as a one shot somewhere else in the program. So if you have a OSR somewhere in the program setting a bit, whenever that bit is referenced elsewhere it reminds you that it gets set for one scan.

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So its just a reminder that the addressed bit is differentiated DFU somewhere else and not a different kind of instruction. Thanks, that makes sense. I know some of ya'lls are are big Omron fans, but I'm with holding judgement for now. Don't expect a new convert to the cult any time soon. Edited by Alaric

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It's a differentiate up contact. With a CJ/CS series program, the DIFU and DIFD instruction as you probably know them are not referenced separately as instructions anymore, you can assign differentiate up or down on any contact direclty in the edit contact window. The -|| |- or -| ||- shows up as a reminder. p.s. you will come by my friend

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OK, I've played with this a bit more now and I just want to make sure - the help file is a bit vague. With the following code: In rungs 0 and 1, when input 1.00 comes on and 20.01 comes on, 30.00 is set true for one scan only, making 31.00 a one shot also. 1.00 can be on for some time before 20.01 becomes true, or vice versa, and the one shot at 30.00 will still function. In rung 2, if 20.01 is already on, and then 1.00 becomes true, bit 31.01 will function as a one shot. But if input 1.00 is on for some time before 20.01 becomes true, then 31.01 will not pulse. Is that correct in Omron-ville? If so its a bear trap I'll need to watch out for, or does Omron handle this with more elegance than the -|^|- instruction in Modicon 984LL?

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Now that I see input 1.00 in rung 2 which in fact I had in mind when talking about setting a difup action to a contact directly , I realise the -|| |- is displayed to reference to an actual DIFU instruction.. I realize now I never really noticed. Your comment sounds fair although I don't know about Modicon. Don't have CXP here either ... sorry for the confusion, shouldn't be posting at these times...

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Your explanation is correct but i do not see why it is a bear trap.... Rung 0 could be seen as a OSR in AB in that once all of the instructions have become true on the possive edge fie the difu... if some one fires a coil of the difu bit then it really comes down to the description of the coil... this would be common acrros all brands of PLC.s The second instance you can use the input in your case as normal / positive edge / negative edge directly. Note that the direct differentiation of a contact is only for the later CJ/CS/CP1H PLC models... Note that you can also use the UP / DOWN instructions inline similar to the OSR OSF bits in AB...

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I think the point you are missing is that the DIFU and DIFD functions are holdovers from earlier model PLC's. The |^| and |v| act directly on the contact and therefore do not require a function, this helps save programming time. OMRON has always been very consistent in that when they add new functions they strive hard to keep the older ones available whenever possible.

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I think Alaric has buried himself under the rock by now LOL

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Ahem... what rock would that be? ABs inline ONS (or OSR in the SLC) is an instruction that works off the change in state of the rung. But if I'm reading things right, the omron @LD, @OR, @AND tinstructions evaluate true on the rising edge of the addressed bit, not the state of the rung. Thats an important distinction in how they operate.

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Another tip, if you havent' discovered already, if you are using an 'I' instruction, such as move, add etc, you can add a @ before the instruction definition, this acts as a OSR, almost the same as a ONS in AB. All depends on how you are using, or wanting to use the OS though

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I don't think it's fair to knock a new user - Alaric is learning and will stop groping around with Omron when he sees some of their benefits. I have been programming with CX-One for 2 years and still learnt something from him. -|| |- Indicates that the bit is addressed with a DIFD somewhere in the program. -| ||- Indicates that the bit is addressed with a DIFU somewhere in the program. -| ||- Indicates that the bit is addressed with a DIFD somewhere in the program. -|| |- Indicates that the bit is addressed with a DIFU somewhere in the program. Cannot find any refernence to this in the Omron Manuals - so I can see why it would be confusing to a new user. Yes OMRON's documentation is lacking in some areas but they have come a long way from the old JanGlish S6 and C28K days. Edited by BITS N BYTES

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I was referring to your avatar... forgive my dull joke. This makes me realize that what's cristal clear to me doesn't mean it is logical, I just happen to understand. But let's get back to the original question. Is it clear now ?

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Yes, and thanks for the help. Up till now my experience has been mostly with AB and Modicon, some GE, a little bit of Koyo, Mitsubishi, some exposure to others. I've been dabbling with Omron for only a couple of months and only seriously the last month. Edited by Alaric

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Summary ... There are four categories of one shot functionality: See Picture Each can be useful in different situations. Nibroc (See Picture at above link) Edited by Nibroc

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Excellent explanation. Where can I sign up for your training course

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There is a great deal of versatility in the latest Omron PLCs that would appear to be absolutely confusing to a newbie to the brand - even to some of us old codgers. Have been using them forever (seems like) and still finding good things. Hope the rock does not crush you - looks dangerous. Enjoy the experience.

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The inline not from that graphic is good to know. Its like the INV instruction in AB PLC5s. I really wish AB had kept that instruction around, it sure makes it easier to program IF THEN ELSE situations.

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Regards the inline NOT FYI Alaric... you can alos directly invert the output coil.. see below.

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Not sure if you mentioned what model you are using, I recall you were looking at the CPM2 range a while back? Is also worth pointing out that not all features are available in all models

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