Yaskawa V1000 Tripping on e-stop? - Page 2
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  1. #21
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    Below are some of the parameters that I use on my V1000 for my lathe, I have also used similar parameters on a larger lathe install. I get pretty instant stops and I also have my E-Stop wired for fast stop input. I have not had any issues with stopping from 2000 RPM in less than 1 second. One of the important settings is L3-04, so try either setting 4 or 7. DC injection as I understand it occurs below b2-01 so more low speed. I use various braking rates, I also use an electronic braking sensor which repeats to better than 0.001" for threading and turning internally.

    A1-02 Control method... [M] 2 Open-loop vector control
    b2-01 DC injection start frequency... [M] 4.0 Hz
    b3-03 Speed search deceleration time... [M] 0.1 sec
    b3-05 Search wait time..0.1 sec
    C1-01 Acceleration time 1... 4.00 sec
    C1-02 Deceleration time 1.. 1.00 sec
    C1-03 Acceleration time 2.. 4.00 sec
    C1-04 Deceleration time 2... 1.50 sec
    C1-09 Emergency stop time... 0.50 sec
    C1-10 Accel/Decel time setting unit... 0
    C2-02 S-curve acceleration at end... 0.00 sec
    C2-03 S-curve deceleration at start...0.00 sec (you may need some S curve)
    C6-01 Duty Cycle...0 (you may need to run standard mode I run an oversized VFD)
    C6-02 Carrier frequency selection... 04 (10kHz)
    L3-04 StallP deceleration selection...7 Over excitation Deceleration3
    L3-24 Inertia conversion motor acceler.. 0.145 sec
    L8-38 Carrier frequency decel selectio... [M] 2 Overload career frequency decreases gradually

    H1 Multi-Function Digital Inputs
    H1-01 Terminal S1 function selection 40 Forward Run Command
    H1-02 Terminal S2 function selection 41 Reverse Run Command
    H1-03 Terminal S3 function selection...12 Forward Jog command
    H1-04 Terminal S4 function selection...13 Reverse Jog command
    H1-05 Terminal S5 function selection...07 Accel/Decel time 1
    H1-06 Terminal S6 function selection...08 External baseblock (N/O)
    H1-07 Terminal S7 function selection...15 Emergency Stop (N/O

  2. #22
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    Hi
    I have added my settings to the end of each line. Not much difference between them.

    Quote Originally Posted by mksj View Post
    Below are some of the parameters that I use on my V1000 for my lathe, I have also used similar parameters on a larger lathe install. I get pretty instant stops and I also have my E-Stop wired for fast stop input. I have not had any issues with stopping from 2000 RPM in less than 1 second. One of the important settings is L3-04, so try either setting 4 or 7. DC injection as I understand it occurs below b2-01 so more low speed. I use various braking rates, I also use an electronic braking sensor which repeats to better than 0.001" for threading and turning internally.

    A1-02 Control method... [M] 2 Open-loop vector control ☺
    b2-01 DC injection start frequency... [M] 4.0 Hz 0.5Hz
    b3-03 Speed search deceleration time... [M] 0.1 sec 2.0s
    b3-05 Search wait time..0.1 sec 0.2s
    C1-01 Acceleration time 1... 4.00 sec 4.0s
    C1-02 Deceleration time 1.. 1.00 sec 2.0s
    C1-03 Acceleration time 2.. 4.00 sec 4.0s
    C1-04 Deceleration time 2... 1.50 sec 2.0s
    C1-09 Emergency stop time... 0.50 sec 0.75s (started with 0.5s but tripped)
    C1-10 Accel/Decel time setting unit... 0 1
    C2-02 S-curve acceleration at end... 0.00 sec 0.2s
    C2-03 S-curve deceleration at start...0.00 sec (you may need some S curve) 0.2s
    C6-01 Duty Cycle...0 (you may need to run standard mode I run an oversized VFD) 0 (HD only option for 0018 model.
    C6-02 Carrier frequency selection... 04 (10kHz) 07 Swing PWM1 to minimize tonal noise.
    L3-04 StallP deceleration selection...7 Over excitation Deceleration3 3
    L3-24 Inertia conversion motor acceler.. 0.145 sec 0.145s (set by auto-tuning)
    L8-38 Carrier frequency decel selectio... [M] 2 Overload career frequency decreases gradually : 1

    H1 Multi-Function Digital Inputs
    H1-01 Terminal S1 function selection 40 Forward Run Command
    H1-02 Terminal S2 function selection 41 Reverse Run Command
    H1-03 Terminal S3 function selection...12 Forward Jog command
    H1-04 Terminal S4 function selection...13 Reverse Jog command
    H1-05 Terminal S5 function selection...07 Accel/Decel time 1
    H1-06 Terminal S6 function selection...08 External baseblock (N/O)
    H1-07 Terminal S7 function selection...15 Emergency Stop (N/O

  3. #23
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    Quote Originally Posted by SomeoneSomewhere View Post
    Whatever braking option you choose, IMHO you should really run it up to above the maximum intended inertia and speed and test it repeatedly. Having the OK vs Fault line between 60 & 67 Hz is not good if you then use a heavier chunk of steel...
    The 60Hz - 67Hz values are arbitrary. The choice of an empty chuck as a test load was also arbitrary. The tests were intended to look at behaviors, not set points. In an e-stop should cause the drive to stop the motor as quickly as possible, without breaking the machine. It should never trip out regardless of speed and load. Given that for a lathe where the vfd has complete control of the energy, it should be able to maximise energy transfer from the lathe spindle to the brake resistor.

    Dazz

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    The real question here is "what IS your E-stop?".

    If it is just another button in line with the regular stop button, just a latching version, then why expect it to be different?

    If it is a different E-stop INPUT, then you should be able to program it differently to the regular stop. Maybe use DC braking, etc. Check the manual for more options.

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    There are no unique braking functions for the fast stop command other than setting a different stop time from the defaults and requires cycling through a stop command. It will go into a free run mode if pushed too aggressively. The other braking parameters I indicated above apply to all VFD braking modes, but you can only brake so fast depending on the momentum in the system. L3-04 is suppose to prevent over voltage/current error and adjust the braking time. Raise the DC injection point. Try a few of the changes indicated to determine the best parameters that doesn't trip out. Pretty much what the manuals says.


    Per the manual:
    C1-09: Fast-stop Time
    Parameter C1-09 will set a special deceleration that is used when certain faults occur or that can be operated by closing a digital input configured as H1-oo = 15 (N.O. input) or H1-oo = 17 (N.C. input). The input does not have to be closed continuously, even a momentary closure will trigger the Fast-stop operation. Unlike standard deceleration, once the Fast-stop operation is initiated, the drive cannot be restarted until the deceleration is complete, the Fast-stop input is cleared, and the Run command is cycled.

    NOTICE: Rapid deceleration can trigger an over voltage fault. When faulted, the drive output shuts off, and the motor coasts. To avoid this uncontrolled motor state and to ensure that the motor stops quickly and safely, set an appropriate Fast-stop time to C1-09.

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    Quote Originally Posted by mksj View Post
    There are no unique braking functions for the fast stop command other than setting a different stop time from the defaults and requires cycling through a stop command. It will go into a free run mode if pushed too aggressively. The other braking parameters I indicated above apply to all VFD braking modes, but you can only brake so fast depending on the momentum in the system. L3-04 is suppose to prevent over voltage/current error and adjust the braking time. Raise the DC injection point. Try a few of the changes indicated to determine the best parameters that doesn't trip out. Pretty much what the manuals says.
    All of these require a worst case approach resulting in a longer braking time. If I set up my drive to include maximum sized job (max inertia) and max speed, the time to stop would be far too long. What is missing is a feature to maximise motor braking effect regardless of speed and inertia. That behaviour cannot be achieved with the currently available settings.

    The solution requires action by Yaskawa. Does anyone have an inside line of comms into Yaskawa?

    Dazz

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    Going to Vector mode and using constant-torque deceleration would work. A larger load would take longer to spin down at the same torque.

    I think you should also try a lower resistance resistor. You are not able to put the full 4kW rating of the motor through the current one.

  8. #28
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    The setting L3-02 = 2 Intelligent stop, fast as possible, appears to be the function I am looking for, but there is no indication that this setting can be used with an external braking resistor. I don't want to try this feature without first knowing that is uses the external braking resistor. I have asked Yaskawa about this.

    I have not studied the details of vector mode and constant torque. The critical question is whether it makes use of a braking resistor on deceleration? I did a search of "vector" and could not find any discussion of vector associated with braking resistor.

    I looked at DC braking but if this was used, I don't think it would be possible to send power to the braking resistor.

    Under section 5.5 E: Motor Parameters, I already have constant torque selected for v/f mode. The problem is that even constant torque on deceleration is limited by how much energy can be dumped into the braking resistor. Reducing the value of the resistor will improve, but not fix the symptoms.

    These drives are complicated. It is hard to be sure that all the setting are right.

    Dazz

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    You're correct that DC injection does not use the resistor; it dumps the energy into the motor instead. This is mildly hard on the motor, but unless you are routinely using the E-stop and stopping frequently it should be fine. It is still better for the motor than DOL starting.


    Under section 5.5 E: Motor Parameters, I already have constant torque selected for v/f mode. The problem is that even constant torque on deceleration is limited by how much energy can be dumped into the braking resistor. Reducing the value of the resistor will improve, but not fix the symptoms.
    V/f constant torque vs variable torque is about the type of load on the motor and the voltage-frequency curve used. Some loads like fans use significantly less torque at lower speeds and there are efficiency advantages to reducing the voltages at partial loads, but for machine tools you want full torque even at part loads.

    Open loop vector is a different way of doing the voltage vs frequency maths, which allows more accurate RPM control and faster reaction, and also allows you to drive the motor based on a torque setpoint rather than a speed setpoint. This means that rather than decelerating at say 15Hz per second, you can also order the drive to apply a torque of say -4 Nm to the load and it decelerates at whatever rate this leads to.

    The braking resistor will still work in this mode. Make sure you re-do the auto-tuning.

    The setting L3-02 = 2 Intelligent stop, fast as possible, appears to be the function I am looking for, but there is no indication that this setting can be used with an external braking resistor. I don't want to try this feature without first knowing that is uses the external braking resistor. I have asked Yaskawa about this.
    I think you mean L3-04 = 2. It looks like you may also need to adjust L3-17 and L3-20 to ensure that the DC braking has time to operate first. L3-11 should also be set to 1.

    It may be that the drive's factory tuning assumes that a certain amount of power can be dumped into the brake resistor, and because the resistor accepts less than that, the drive pulls more energy than it can handle and overshoots.

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    Per table E1-01, you probably need to set L3-17 above 394V or it is never going to allow the motor to brake hard enough to engage the transistor.

    Out of curiosity, where in NZ are you?

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    Hi
    Just got an answer from Yaskawa.
    They recommend set L3-04=0 and then lower C1-01 as much as possible.

    I see Yaskawa has introduced the GA800 and GA500 drives. Probably the best choice for new installations.

    I live in Wellington.

    Dazz

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    Huh. Same. Maybe when this has all blown over...

    That's the slow option, there. You'll be decelerating slower than necessary with anything other than a high-inertia high-speed load.

    Hmm.

  13. #33
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    Their recommendations do not make any sense, and C1-01 is acceleration. Essentially they are telling you to set a braking time with overload parameter until you do not get a fault. This will be different based on the chuck weight and speed, gear selection, and how often you brake. Parameter L3-04 is specifically for preventing an OV fault, why not just try using it and adjust the Emergency stop time down in increments until it no longer changes the stopping time and then add maybe 0.2 seconds and be done with it. There is no magical parameter that is going to stop your lathe any faster. You can try setting 01, 03, 04 and 07 for L3-04 and see which works best. The manual states "Set parameter L3-04 = “3” to generate the shortest possible deceleration time." It really doesn't matter how it is stopping the lathe, as long as it is stopping the quickest. I have done this with bigger lathes than yours and it has worked well, but your mechanical foot brake will ultimately be a better option.

    You also have a 3.7kW rated VFD for a 4kW motor, so there may be some limitations with regard to how well the VFD can dissipate the braking energy. On a similar 5 Hp lathe system that I worked on I went with the 10Hp CIMR-VU2A0030FAA using a buss choke with single phase power source.

  14. #34
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    Quote Originally Posted by dazz View Post
    I see Yaskawa has introduced the GA800 and GA500 drives. Probably the best choice for new installations.
    From what I've read the V1000 is a well regarded and popular model. I don't recall anyone having problems or complaints with them. Maybe yours has a problem, or you're just doing something wrong.

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    Quote Originally Posted by ptsmith View Post
    ... or you're just doing something wrong.
    That was my first assumption.

    I did some more testing and tried the things suggested by Yaskawa. They did not achieve what I wanted. Their suggestion was to extend the deceleration time until the vfd didn't trip. That suggestion makes no sense. To cover all situations, I would need to load the lathe with the highest inertia job running at the fastest speed, then set the fast-stop deceleration to a time long enough to prevent a trip. That could be a very long time. Far longer than it needs to be for a low inertia, lower speed job.

    What I want is for the VFD to match the regen power to the capacity of the braking resistor to absorb energy. If the two are matched, the V DC bus will not change and the vfd won't trip. There is a mode that does that, but it does not work with a braking resistor.

    According to Yaskawa, none of the Yaskawa drives, including the G series, has this feature. I think that is a major deficiency.



    Dazz

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    As several have mentioned, L3-04 is to prevent an OV fault, essentially it will switch braking on and off to stop in close to the least time that will avoid tripping the unit off and coasting the whole way. It has some hysteresis, I assume so it may stay "off" and not braking longer than absolutely necessary, but that should not extend braking tome too far.

    Going with the lowest value resistor that is allowed will also help, and ensuring that the brake is enabled to use the maximum possible duty cycle that will not kill the resistor will get you to the maximum braking capability.

    If you need better than that, the best solution is going to be an oversized VFD, one for which your motor is not a maximum load, but only medium. That will allow a more rapid braking without a trip-off, because of the reserve above your motor power, which means more bus capacitor, lower resistor value, and so forth.

    You may already have some extra margin, as the next drive above 4 kW is 5.5 kW, giving you a certain amount of extra. If you happen to be using a 3.7 kW, then you are slightly behind the 8-ball to begin with.

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    Quote Originally Posted by JST View Post
    As several have mentioned, L3-04 is to prevent an OV fault, essentially it will switch braking on and off to stop in close to the least time that will avoid tripping the unit off and coasting the whole way. It has some hysteresis, I assume so it may stay "off" and not braking longer than absolutely necessary, but that should not extend braking tome too far.

    Going with the lowest value resistor that is allowed will also help, and ensuring that the brake is enabled to use the maximum possible duty cycle that will not kill the resistor will get you to the maximum braking capability.

    If you need better than that, the best solution is going to be an oversized VFD, one for which your motor is not a maximum load, but only medium. That will allow a more rapid braking without a trip-off, because of the reserve above your motor power, which means more bus capacitor, lower resistor value, and so forth.

    You may already have some extra margin, as the next drive above 4 kW is 5.5 kW, giving you a certain amount of extra. If you happen to be using a 3.7 kW, then you are slightly behind the 8-ball to begin with.
    Hi
    At the time of purchase, a 3.8kW VFD was the highest power 1phase VFD available.

    I have not been able to find the rating of the braking resistor switch. That will limit the lowest resistance of the braking resistor.

    My plan is to look at using DriveWorksEZ to implement a control loop to limit the regen current/power during deceleration. To do that I will need the Ethernet version of the options card. Yaskawa are unable (unwilling?) to advise if this plan can work. Based on what I know, it should work. There is too much that I don't know about the drive to be certain it will work.

    Due to other commitments, it will probably take about a year to get that done.

    Dazz

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    What is the braking time that you are getting now when you hit the E-Stop and what is the braking time you want. I just do not follow how you are going to achieve anything better than what L3-04 does. In essence it modulates the braking so an OV does not occur and uses different methods to dissipate the excess voltage. I have a similar sized lathe to yours and have also installed the 3 phase V1000 running in a derated mode and also on larger lathes and achieved 1-2 second braking times. These lathe come with a mechanical foot brake, which is typically a quicker response than reaching over and hitting the E-Stop. I just do not see what you are going to achieve with a control loop beyond what they internally already provide.

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    Hi
    The fundamental problem is that the Yaskawa vfd's (all models) do not have the feature I am looking for. No amount of tuning parameters will solve that. DriveWorksEZ offers the potential to create the missing feature myself if I get the Ethernet option card. The Ethernet card is required to provide the data sample rate needed to evaluate the transient response of the vfd. The standard serial connection I am currently using is way too slow.

    I trained as a weapons engineer and the thesis for each of my Masters degrees were based on control system engineering. I am accustomed to precision motor controlled systems. I am reasonably confident that I can develop an appropriate algorithm to do true fast stops. I don't yet know if there is some limitation or constraint that will prevent me achieving the aim.

    My lathe left the factory without an e-stop, when that was acceptable. I have fitted a e-stop switch to a control panel on the head stock and also one on the tailstock end. I usually try and work on the tail stock side of the cutting tool so I can see the work and be clear of the firing line if anything lets loose. For me the double e-stops are a better solution than a foot bar.

    Dazz

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    I would still strongly suggest using DC braking for E-stop. A safety feature this twitchy is not a good idea, even if you can make it more reliable. The extra heat dumped into the motor is negligible; less than a DOL start that the motor was intended to undergo.

    I still feel this is an issue with the parameters surrounding the DC voltage regulation. It's expecting the DC resistor to have a bigger faster impact than it does due to the reduced current.


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