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goargamo

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  1. Hi everybody ... again it's me with my incremental encoder, I've tested several things but I stil can't find what am I doing wrong and I was hoping you could help me some more. The thing is... I've a 2,000pulses/rev encoder (don't ask me why jaja) and I'm sending its signal to a Unitronics M91-2-T1 PLC, but I haven´t been able to count correctly the revolutions I am doing. Supposedly I preseted my encoder properly, I declared I0.0 & I0.1 as high speed inputs (Hardware Configuration ->M91-2-T1 -> HSI -> High Speed Shaft Encoder (x4)), and I did a Ladder Program that sums +1 and resets the memory where the pulses go, every 8,000 pulses. Also, I saw the output of the encoder with an osciloscope and they seem to be right. Channel A and B are giving square signals which are 90° out of phase, BUT the Z channel gives me nothing more than trash, it is a noisy signal with no pattern at all (I know this PLC doesn't have an input for this channel but never the less it seems strange to me). Finally the frecuency I'm working at: my application has a rotatory velocity of 4.8rev/s (aprox) encoder = 2000pulses/rev input = vel * encoder = 9,600/sec The high speed inputs of this PLC are able to work with frecuencies up to 10,000Hz, I'm working very near the limit but still when i slowed down my application i didn't work correctly. I think my error is in the PLC: maybe the frecuency, or maybe the I didn't declare the High Speed Inputs in all the required settings. Thanks a lot to any idea
  2. Thanks I will do that test with a low frecuency to see if i´m really getting 8.000 pulses per revolution. Thanks a lot
  3. I´m using this encoder because it was the only one i was able to get (the supplier of the company only had this one in existence) =s. Yes the only thing i'm doing is counting turns i don´t really know why this is happening. To try to correct the error in the count of turns i have modified the 8,000 pulses corresponding to a turn to a different number (6,810) and i'm getting a smaller error but i thing this shouldn't be this way, i'll show you the ladder i'm doing so hopefully you find an error jajajaja, thanks a lot Joe
  4. Hi Joe. I will check that. Yes, i'm resetting my count every 8,000 pulses (supposedly). The frecuency coming into the PLC is about 300rpm, (5 revolutions per second x 2,000 pulses per revolution = 10,000 pulses/second)... is this frequency to high =s??? Thanks again
  5. Thanks for the info Joe... I connected the shield (FG) to ground but I´m still having kind of a problem. Im using an incremental encoder of 2,000 pulses, and in my program i preseted that every 8,000 pulses i should count a turn (8,000 because i'm usign a "high speed shaft encoder x4"). The thing is that i'm not counting the number of turns i should... ¿do you know why this could be happening?, my PLC is a M90.2.T1 Thanks again
  6. Hi everybody, i was wondering if someone could help me with a doubt i have concerning to the conections of an incremental encoder. I have this encoder with 6 different cables: 1) Vcc 2) GND 3) channel A 4) channel B 5) channel Z 6) "shield" fg I connected Vcc to 24volts dc, gnd to ground, and channels A and B to the high speed inputs HSI.0 and HSI.1 respectively... MY DOUBT IS ¿¿¿where shoud i connect "Z" and "shield", or should i leave them unconnected??? Thanks a lot for your answers....
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