Jog on a lathe

I bought a VFD and a 3-phase motor to update my semi-crappy lathe.
The VFD supports a jog function and the way I'm going to use it is to
have a switch for JOG on the control panel and then (in JOG mode) the
Run switch moves the motor at a very slow rate until the Run switch is
released.
I never saw a lathe that had a Jog feature. How do they typically work?
Do you press the Jog button and it moves, or is it more like in mine?
Jog seems useful. Never having seen it, I would guess a Jog button with
"move while pressed" would be the way it should work, but can't see any
way to make that happen with the capabilities of my VFD.
Just curious how it normally works.
P.S.
I probably wouldn't even have asked this question but the content of
this group is verging on spam. At least I made an on-topic post.
Geeze, is there any way to get it back to having the majority of posts
with some metal content? A little bit of Off-Topic is ok but I find
myself wading through the subjects and deleteing 80% or more without
even the slightest desire to read them.

Reply to
xray
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Reply to
Ned Simmons
This is how I did it on my Sheldon R15 lathe. It has a number of gearboxes that don't always engage right where the machine is sitting. The jog button makes my Tosvert VFD run forward at 5 Hz, and it just creeps until the gear of clutch dog drops in.
The combined function on yours might be dangerous. If you think the jog switch is on, and hit the run button expecting very slow movement, but it goes to normal speed instead, somthing, or you, might get hurt.
Jon
Reply to
Jon Elson
Its a Hitachi L200 Series inverter.
I have it configured in 3-wire mode which seems like the sensible thing for a lathe -- Run, Stop buttons and F/R switch. The default mode is 2-wire: F-run, R-run. In either case, the jog function just seems to modify the operating speed for the normal run/stop controls.
I did figure out a way to wire it so my run button applies stop when released in jog mode, but can't see a way to get one-button that sets both jog and movement out of this VFD.
Reply to
xray
I've never used that drive, but I just took a quick look at the "Quick Reference Guide"...
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Look at Func Codes C001 thru C005 on p.20 and the corresponding option codes on p.23 . I assume you're using the defaults for C001 and C002 which make terminals 1&2 the RUN/STOP terminals. Try changing C003 to code 06, which appears to make terminal 3 function as a jog input.
I'm extrapolating from experience from other drives, so you ought to read the doc about these functions in the full manual, but I'm quite sure this will get you started in the right direction.
Ned Simmons
Reply to
Ned Simmons
Thanks for the reply, but I have read the full manual. The defaults for C001 and C002 set 2-wire mode. I think this sucks for a lathe. One button is forward-run while closed and the other reverse-run.
I set it up for 3-wire (C001 = 20, C002 = 21, and C003 = 22.) This is more like the original lathe controls with Start, Stop, and F/R. I set C004 = 06 for Jog. When jog is closed, the operation of start, stop, and F/R are modified to run very slow, but there seems to be no sensible way to get it to move in jog mode with just one button.
The function of jog is described in the full manual:
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on page 4-15 (143 of 280.)
That description talks about the default 2-wire control signals, but it works the same with 3-wire -- just replace the transitions of [FW], [RV] in the figure with [Start], [Stop] modified by [F/R].
I have used 2-pole switches for Jog and the Run button, so that I can make the Run button momentary in Jog mode (Stop is applied when the Run button is released, rather than having to hit the Stop button as in normal mode.) This seems to be the best I can do unless I burn my own microcontroller to toggle control lines for Jog.
Reply to
xray
I had the same issue. The jog was just another preset speed. Add a diode from the jog button to the run forward. Then when you push the jog button it will set the speed and start the motor. I used an 1N4003 because I had them lying around.
Wayne D.
Reply to
Wayne
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After looking at the manual I can't see an obvious mode of operation that will do what you want either, but I wouldn't give up without talking to tech support at Hitachi. The manual seems pretty good, but there may be some non-obvious setup that'll get you what you want.
Failing that, I don't think you'd need a uP to get the job done. Set up a pair of cube relays and 3 PBs to emulate a reversing motor starter and set up the drive for 2-wire control (p 4-12). Add two PBs that invoke the jog speed and energize the relays without latching them and I think you've got what you need.
You may find that you don't need the jog speed at all. It may be more convenient to adjust your speed pot for jogging rather than having a fixed jog speed.
Ned Simmons
Reply to
Ned Simmons

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