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Joe Grove

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  1. Thanks for staying with this post. I dont believe i have monitored M18 and 10 for errors. I am not using MB27 or MB3 for any other functions within the program. The first move is not really supposed to complete, it is supposed to see the sensor before completion. Once the sensor is tripped we overwrite the previous PTO command with the one to terminate the move. We are not detecting the end of the move by any feedback device the move is completely open ended. Heres the puzzling thing - the code and stepper system system works perfectly at just about every speed from 3000 up to 18000 pulses. I noticed this condition while testing random speeds - so yes works great at higher speeds. When it overshoots it appears to be relatively conistent, but the overshoot is huge. for example my second move is 1/2 inch it overshoots anout 8 inches. My stepper resolution is set to 1600 PPR and can accept up to 200kHz. I have attached the program for you to evaluate. Maybe there is a better method??? Also, the program altered from the original in which i subract 11 from the first move's velocity decreasing the chance of the issue, but i would like to eliminate if possible. I have posted another entry in the forum asking in more detail for help with programming. thanks, Joe gap sensor program.vlp
  2. using a V130 and PTO output 0. Need help with a method to a very simple Trapezoid stepper move. Basically there are 2 physical inputs. one input starts the move and the second highspeed input finishes the single move. when the start input goes high, the motor will start moving at a specific speed XXX and while the stepper is moving the instant a second input is tripped (rising or falling edge) the motor continues to move at the same speed XXX but stops at a predefined exact distance. The move must not stop or pause and is a very quick move.
  3. thank you for the reply. I had thought that there may be an issue as you desctribed so i performed a test in which i took the motor and driver out of the system and just let the plc pulse while watching the PTO Status. It is interesting because the same thing happens i activate the first jog move with a speed of 8650 and manually trigger the sensor and it dramatically overshoots the target distance. when i use a speed of 8649 it works perfectly.
  4. I have a small issue while sending a move command to a stepper drive from a V130-33-TR34. We have a strange occurrence at a few speeds. We are sending a pulse train at 8650 speed with a distance of 20000 -this is basically a jog move to until a sensor is activated. Once the sensor is tripped we move a predefined distance (600 pulses) at the same speed of 8650. The way this is done is that in the ladder logic the jog move is started based on the rising edge of an input to the plc then on the rising edge of the sensor input a second move command is sent with the new distance. We do not issue a stop between the two move commands, we simply issue a second command while the first move is in motion creating a single smooth trapezoidal move. This works great with the exception of a handful of speeds (frequencies) 8650 being one of them. When 8650 is used the second move (600 pulses) is ignored and or is altered and overshoots the gap sensor and another gap is sensed with another rising edge and the system goes into a cyclic process with no end. If we use 8650 as the speed for the jog move and another speed (ex 8649) for the second move (600) the system performs perfect and stops exactly where expected.
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