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evgeny

"instabilities” in function CTBL

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In the process of work, we found out that there are “ instabilities” in function CTBL. Out of 12 comparisons, the first one and the last one (most frequently) do not function (sometimes but not always !!!) . I changed the “min Cycle Time” to 20 ms and the dysfunction happens less frequently but still it happens sometimes. Why do the dysfunction happen and what is its nature? If I did everything correct or I should have done something else? What else can I do? I use: CPM 2A Encoder 1000pulse/rev I would be very grateful for your help. Evgeny Mefozer_bazek_line1_T_2L.cxp

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What are the DM values of DM 19-36? Your program only sets DM0-DM18, but you are using 12 comparisons.

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Jay, thank you for answer The system is: the cart which after getting the portion of dough puts it into one of the five cells. On its way back , it gets the information about the empty cells. The information about the distance to the points, where the detector has to determine if the cell is empty or not, is located in DM0 - DM18 (Decrement direction - subroutines #F001 - #F005). The information about the distance , where the cart has to stop and drop the portion dough is in DM19 - DM36 (Increment direction - subroutines 006 - 011) . The problem is: sometimes (not always) subroutines 0 and 011 does not function.

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Please read the comment in the previous post regarding: It is not possible to specify more than one comparison direction condition for the same target value in the comparison table. It's possible that the values that are calculated for DM19-32 are conflicting with the ones hardcoded in your proogram.

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Hi Jay, I have read your comments but if you have noticed there is no” the same target value” for two directions. Increment direction: DM1 – 6080 DM19 – 1600 DM22 – 2800 DM25 – 4000 DM28 – 5200 DM31 – 6000 Decrement direction: DM4 – 900 DM7 – 2000 DM10 – 3200 DM13 – 4400 DM17 – 5600 DM36 – 0 Can there be some other reason? Evgeny

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OK. I see where you are calculating for incrementing. I don't see any overlap on the presets. Have you done your speed calculations as far as maximum rpms on the encoder? Remember that differential mode is limited to 5khz.

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Hi Jay, I've got your reply but, as a matter of fact, I don't use diferential mode. I tried to use the Pulse+direction input mode or the Up/Down input mode.The input frequancy is not more than 1.5 khz Don't you think that the problem can be connected with the "min Cycle Time”? Or may be the problem is with the hardwear? Evgeny

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The high speed counter interrupts are not scan dependent, therefore "min cycle time" will not help. I do not know why you are missing the reset on 200.00 and 200.01, but since the rest of the presets are working, I do not suspect the hardware. I am assuming that the reason that you are concerned , is that Sub 0 and Sub 11 are your end presets and that you are driving the cart off the end of the track. Perhaps you should back up the encoder with some end safety limits. Also could you do a backup CMP with 232 in case the encoder misses the end limit?

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