Centroid Community CNC Support Forum

My Tree CNC lathe also has an 8 position hydraulically operated ATC turret. It has 8 individual switches to report the current position, rather than the more normal 3 or 4 line BCD / Gray code. They change state slightly ahead of the turret reaching the lock position, so there is a time delay parameter that needs to be optimised using trial and error to get a reliable, consistent parking. The time delay is broadly the angular difference between the turret and the switch divided by the angular speed.

To make it work, I had to modify the PLC code with some helpful guidance from cncsw. In my case, I simply have one solenoid that takes care of unlocking and rotating the turret (when energised), then stopping and locking it (when de-energised). There is also a switch that reports when the turret is locked in position in case it doesn't park cleanly.

As for the Gray code and whether the MS turret uses its own sequences, IIRC there is a spreadsheet that allows you to set up your own bit sequence. I may misremember but if not, you should be able to use the std 3 or 4 wire grey code option to do what you need. I'd have thought Gray code would be more robust than the timer approach.

As far as turret-position feedback, the general method that Centroid calls "gray code" should work with the Mori Seiki design.

That is because it is not limited to Gray Code, but in fact can work with any system where there is a group of inputs that close in a unique pattern for each turret position (whether binary, BCD, Gray Code, or the typical Mori Seiki pattern of closing a different two of the five sensors in each position).

Unfortunately, the built-in support probably does not allow for five inputs, so you will have to write your own custom logic for that. Also, it is unlikely there is built-in support for a two-speed hydraulic turret (one that rotates fast until it is within one position of the target, then rotates slow until final arrival).

Marik: does your SL2 turret have two-speed operation? Or does yours have an electric motor for rotation, rather than a hydraulic motor? The initial video you posted showed a machine with a hydraulic motor for turret rotation, so I assume that is what you have.

In my recent experience with Mori Seiki hydraulic turrets, the unlock/lock logic is also a little specialized: approaching the final target, they go into an "up free" state, where the turret-unlock solenoid coil is turned off, but the turret-lock coil has not yet been turned back on. This allows the turret to continue to move until it hits a stop at the final position; then the PLC can turn the turret-lock coil on.

So, the bottom line is that you will need to do some custom PLC programming.

Thank you!

Now I am not sure it has electric motor, or some hydraulic assistance, as well. On top I can see a motor and also there is 3 phase wiring. When turret rotates it stops by each station for a second until it reaches correct one. There are thumps at the stops—sounds like there is some mechanical stop inside on each station.

I took the back of the turret apart. There are 6 proximity switches—one looks different model… perhaps home?

Here are the pictures of the motor and back of the turret. I tried to upload the short video of the turret in operation, but the system showed error for .mov extension.

Best, M

For movies, upload to YouTube and link here.

If there is a three-phase motor, and multi-tool rotation stops momentarily at each position, then it is an electric turret with a Geneva mechanism, with hydraulic unclamp/clamp.

Chances are good that five of the sensors are for tool positions, and the 6th is for clamped/unclamped feedback.

That is a fairly easy turret to control, but someone else will have to tell you how to negotiate the existing options built into Acorn lathe PLC programs.

Here is the turret operation:

https://youtube.com/shorts/dA7_bW1nPM4

cncsnw wrote: ↑Tue Feb 21, 2023 4:26 pm
Chances are good that five of the sensors are for tool positions, and the 6th is for clamped/unclamped feedback.

Thanks! Yes, I double checked and judging by corresponding teeth on a plate below the 6th switch indeed looks like for the turret clamp/unclamp operation.

Now the question is how to connect all of that to Acorn.

Thanks, M

Our Hitachi Seiki slant bed has a hydraulic tool changer.

I mapped out all the functions and had the wires connected and ready. Mark (cncsnw) programmed the PLC. Wise $ spent.

I think I could send you the code as a sample but have Mark help you as timing and other details are critical.

Been working perfectly for 9 years. Absurdly productive lathe.

I am not sure how to connect the turret to the Acorn. I checked the wizard and did not find any lines with Turret out, turret in. Could not find any schematics with such arrangement. Anybody could help?

Thanks, M

Marik wrote: ↑Tue Feb 28, 2023 1:31 pm I am not sure how to connect the turret to the Acorn. I checked the wizard and did not find any lines with Turret out, turret in. Could not find any schematics with such arrangement. Anybody could help?

Thanks, M

turret in out?