Hitachi vfd programming question

[medic0079]

So I got the mill up and running and decided to add a jog function primarily for starting taps I want to be able to hit the button and have the machine coast to a stop with no braking. My options for no braking after stop is 00-free running after jogging stops disabled during operation, and 03-free running after jogging stopped enabled during operation. What does the enabled/disabled during operation mean? Also does this mean that the mill will start running after stop or just coast to a stop like I want. It is a ne-s1 series vfd. Also is there a way to incorporate the fwd/reverse switch in the jog so I can jog in reverse? Thanks for the knowledge
Noah

 

[JimDawson]

Congratulations on getting your mill running. I want to apologize again for specifying the wrong contact blocks. I looked at the ones I have here for my mill and realized I had the same problem.

To answer your question: The way I do it is to allow the breaking, and hit the stop button as soon as the tap contacts the work. It still takes a second or so for the spindle to ramp down. This gives the tap a 2 or 3 thread start.

In this case you would only have to wire in the jog button in parallel with the E-Stop button, if it is wired like we talked about. This would allow you to jog both forward and reverse.

As far as the programming, I would just try it in the different configurations and see what gives you the desired result.

 

[medic0079]

Grrr this isn't working out as well as I had planned. I wired the jog switch into terminal 3 and programmed that for jog function. I press the button and nothing happens. I was wanting the jog function to turn the machine on to a preset speed for a second then coast to a stop when the switch is released. I have a 10 second acceleration and deceleration for the motor programmed default. I guess I can just bypass the stop switch and put the jog button to turn the machine on then off when the switch is released, but with the long start up time and shutdown time IDK how this would work out. any ideas? also is the 10 second start up and shutdown necessary? can this be shortened to say 3 seconds or will this damage the motor/vfd
and I thought I was beginning to understand the VFD

 

[JimDawson]

Grrr this isn't working out as well as I had planned. I wired the jog switch into terminal 3 and programmed that for jog function. I press the button and nothing happens. I was wanting the jog function to turn the machine on to a preset speed for a second then coast to a stop when the switch is released. I have a 10 second acceleration and deceleration for the motor programmed default. I guess I can just bypass the stop switch and put the jog button to turn the machine on then off when the switch is released, but with the long start up time and shutdown time IDK how this would work out. any ideas? also is the 10 second start up and shutdown necessary? can this be shortened to say 3 seconds or will this damage the motor/vfd
and I thought I was beginning to understand the VFD

You should be able to wire the jog switch across the OFF ('E_STOP') switch. This way it would break the circuit the For/Rev switch, when released. It would override the 'E-STOP' switch when pushed. I don't use a jog on my mill, never really found the need.

Unless there is a separate parameter for the jog accel/decel you would be using the run accel/decel parameters. I have mine set for a 4 second accel, just to get a bit of a soft start, and a 2 second decel. In order to use the 2 second decel, I had to use a breaking resistor. This is the minimum time I could use reliably without getting 'Bus Over Voltage' trips. IDK if your VFD has a provision for a braking resistor. Your decel is limited by the amount of regenerated power dissipation the VFD will handle. You can always set the parameters to coast to a stop, then the regen power is not an issue. You should be able to set the accel to near zero without a problem.

To get all of the features you want, it may be necessary to add some additional control wiring.

 

[medic0079]

I can't add a resistor to my mill but coast to a stop is what I want it has a manual break anyway. Would it be ok to set it to zero decel time and coast to stop without problem then?

 

[JimDawson]

I can't add a resistor to my mill but coast to a stop is what I want it has a manual break anyway. Would it be ok to set it to zero decel time and coast to stop without problem then?

I'm not sure that setting the decel time to zero is the way to do that. Every VFD that I have seen will try to decel in the time set, in the case of zero it would try to stop instantaneously, however, in your VFD, it could be that setting to zero is the way to set coast to stop. I think you have to set another parameter for coast to stop.