View Full Version : A axis direction change?


nervis1
08-06-2005, 08:40 AM
Anyone know how to change the A axis direction at the control on a Fadal?

I need CW to be CCW.

HuFlungDung
08-06-2005, 01:32 PM
Is there no parameter setting for that?

Other than that, a knowledgeable tech could likely physically reverse the motor polarity and encoder leads to reverse it.

Al_The_Man
08-06-2005, 01:56 PM
With Fanuc, Mitsubishi and others, there is a parameter bit to set for a 1 for + or 0 for - clockwise, If can get hold of a Fadal servo parameter sheet it may show the same set up.
Other than that you could go the route Hu mentioned of lead reversal, the only problem with that if it is an AC servo, there could be problems with the commutation signal.
Al.

alloyspec
08-07-2005, 09:23 AM
Most people that have Fadals mount the indexer on the right side of the table as the plug for the cable is on that side. If you mount it on the left side of the table it will seemingly rotate in the opposite direction (not really). May not help in your situation though. Do you have programs from some other machine you want to run on this Fadal? Minor program edits will change the program, unless you have a ton of index blocks.

Alloyspec

nervis1
08-07-2005, 03:16 PM
I called a tech this Sat and he tells me no, no way.

Seems like there should be a parameter for this.
I thought of mounting on the left side of the table but the cable would cause a lot of problems, it would be very difficult to keep it out of the way even if it would reach. The natural position would put the cable across the middle of the table and routing it around with cable ties or something I don't think it would reach.

HuFlungDung
08-07-2005, 04:02 PM
Dave,
So is this a brushless motor setup?

nervis1
08-07-2005, 04:54 PM
No, brush DC servos Hu.

I asked him about flipping a couple of wires but he said that several other things would have to change as well. Ward mentioned that the resolver direction would have to be flipped as well.

Al_The_Man
08-07-2005, 05:08 PM
If you have a resolver instead of an encoder, I would say that you would have to swop the DC to the motor and one pair of the secondary leads of the resolver, In the case of an encoder it would be the A & /A channels. If you change the direction of both motor and feedback, the control does not know this, as long as one confirms the other.
Also if the motor has a tach, that would have to be swopped also.
I am suprised they do not have that in the control, because if it does not, then when a Machine is set up for +- direction this physical process would have to be gone through.
Al.

screensnot
08-07-2005, 05:27 PM
Can't you just mirror the A axis?

Add this to your program:
G51.1 A0

alloyspec
08-07-2005, 07:27 PM
Are you using a Fadal 4th axis or some other brand? If the motor mounts direct like the Fadal unit does, there is a solution. But it is not a quick one. The 4th axis on my machine at work is a SMW that we mounted the motor above and on the back side of the indexer.With this setup the motor does not hang way out to the side like the Fadal unit. We use a gilmer belt with one-to-one ratio to drive it and this reverses the direction from standard. I am not sure you would want to go to this much trouble though.
Alloyspec

nervis1
08-07-2005, 09:35 PM
The table is a Fadal VH165.

Never heard of G51.1, I'll check that out.

Thanks

ZachB
08-08-2005, 02:24 AM
Iam not sure if iam reading question right, but I usually use a positive A or negative A value to make our 4th Axis rotate eather direction. And if my post is posting the opposite of what I want, I usually mass modify A to A-. Forgive me if iam way off on this subject.

Z

Neal
08-08-2005, 05:27 PM
Neveris1--
Depending on which version controller card you have the directional change can be acomplished by a simply jumer change. The -6 cards have a jumper setting at J4 (i think) jumper block that allow reversals. If its earlier, let me know and I'll find out what to change.
Neal

nervis1
08-08-2005, 08:00 PM
Yes it is a -6 card. Do you know exactly what I need to do with J4?

I don't see it in the manual (may have missed it though, I'll look again). Thanks for the help Neal.

Neal
08-09-2005, 07:04 PM
Nervis--
Look on the board itself. Locate the jumper block at J4. It will have the jumpers for X, Y, Z and A axes and spindle. On one end of that block is Rev Dir. Place a jumper on the REV DIR pins. Also on the 1010 controller card there are two wires that go into the small black connector on the edge of the board. Reverse these wires as well. Deed Done.

Neal

Sibole
08-24-2005, 07:56 PM
Iam not sure if iam reading question right, but I usually use a positive A or negative A value to make our 4th Axis rotate eather direction. And if my post is posting the opposite of what I want, I usually mass modify A to A-. Forgive me if iam way off on this subject.

Z

Exactly

ZachB
08-24-2005, 08:45 PM
Search and replace just for indexing would work but, true 4 axis machining he wouldnt be able to just change positive and negative values on the A axis. It would seem like your post processor could be edited to do what ya needed tho.

Z

nstaley
10-27-2006, 09:38 AM
Have you tried A- or A+

nervis1
10-27-2006, 11:49 AM
Read the responses from Neal, he had the answer as usual. :D