hydraulic motor lathe turret, keep switches or switch to rotary encoder ?

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10 May 2022 22:58 #242533 by smc.collins
These resolvers are control transformers. So I will be converting to rotary encoders.

Yay

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11 May 2022 10:05 #242610 by andypugh

These resolvers are control transformers.


So, three-phase output?

So I will be converting to rotary encoders.


With DC servos, tachometers and velocity-mode drives I would suggest that linear scales for position feedback might give the best results. Apart from anything else you can then just ignore the resolvers, no need for modifications in that area.
The following user(s) said Thank You: smc.collins

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11 May 2022 11:09 #242619 by smc.collins
Currently the resolvers sit on the lead screws, I'll put the encoders back on the lead screws, there's no place linear scales can go

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15 May 2022 19:43 #243047 by smc.collins
I'll make you a deal, I will give you the resolvers and the resolver card " no idea if they are worth anything to you" in exchange for your help getting my tools changers working on all of my machines. I think I have a pretty good handle on everything else.

I have 3 resolvers coming off this cincinatti

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17 May 2022 08:13 #243133 by andypugh

I'll make you a deal, I will give you the resolvers and the resolver card " no idea if they are worth anything to you" in exchange for your help getting my tools changers working on all of my machines.

I probably have enough resolvers for my immediate needs, and I am (probably) several thousand miles away. 

But, you can count on my support with the rest of the retrofit. 

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17 May 2022 22:42 #243216 by smc.collins
Post isn't crazy exspensive, I have a TON of cincinatti Arcamatic 900 parts, if theres a need for small stuff, I will happily ship to ya. it's just going in a landfill or being scraped for precious metals, seems like a waste,

Speaking of, there a TON of gold plated UV eprom, I haven't looked yet but probably 2816 or 2832 Intel chips and a but load of them and some ram as well. If you want "ill pull chips give you some part numbers, if they help you great, if not, I will happily Ebay them to keep them from going to waste.

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17 May 2022 23:11 #243218 by andypugh

Post isn't crazy exspensive, I have a TON of cincinatti Arcamatic 900 parts, if theres a need for small stuff, I will happily ship to ya. it's just going in a landfill or being scraped for precious metals, seems like a waste,

Well, I do like resolvers :-)

 

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24 May 2022 22:47 #243730 by smc.collins
all 3 of the resolvers are out, I need to know where to ship them, they aren't very big BTW

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30 May 2022 03:14 #244178 by JR1050
To use the bcd from the encoder on your turret , you will need to wire them into four inputs and use the wsum component to create a decimal number that indicates tool position.
This is not with out pit falls, I’m guessing that your turret encoder is similar to a Hardinge and lacks a parity bit. It is very easy to get a race condition or a incomplete read of all four bits , resulting in a wrong tool position. It usually happens with the second most significant bit . The result is getting any tool up that has a “2” in it that is before the desired tool in the turret. Using a “ debouncer” or a delay after it reads the encoder can keep this from happening.
Is this a bi directional turret? I wrote my indexing routines before the carousel component and had to write logic to determine the direction that resulted in the shortest tool to tool path.
The resolvers you mention are very common, they were used on many American machines , all dc motor Fadals have them. They are a “ hi output “ type , will need the 7i49hv or use channels 3-6 on a standard 7i49. Resolvers are analog devices, they go directly to the inputs on the servo control boards not thru any kind of serial interface. The motors are dc brush motors, there is no reason for the resolver to go to the drive.
You mentioned the resolvers are coupled to the screw, are the tachs on the screw also? Many machines in the early 80s/ late 70s had a “ feedback unit “ that consisted of a geared tach and resolver . If this is the case , a kunundrum just appeared. You cannot disconnect the motors from the screws to test, they will run away with out feedback, at the same time if you leave them on the machine and get something wrong and the axis takes off, you could have a crash of monumental proportions.
What brand of motors do you have? Getty’s, Siemens, Porter peerless? Are the drives transistor or scr?
On the bright side, you can end up with excellent resolution with geared resolvers, the ppr count out of a 7i49 is 16k, multiply that by the gearing and you can end up with 100k ppr !!
Consider a Pokeys for an operator interface, it would allow you to use the extra serial on a 7i77 for machine I/o if you went to encoders .

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31 May 2022 17:39 - 31 May 2022 17:40 #244299 by smc.collins
I swapped in 4096 ppr encoders, the tach wiring goes to the drives, thry are reliance drives and motors afaict


The switch component has a 4 switch array with 16 combinations. Turret only spins one direction
Last edit: 31 May 2022 17:40 by smc.collins.

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