Z - axis brake delay

[RoblesEng.]

Hello, everybody. Thanks for all post that help me to solve many problem that I found during the retrofit, but I cant solve one problem. My machine is a Pratt and Whitney Fanuc Drill Mate of 1990. This is the Third time that I retrofit It, two times with Mach3 and CS-Lab and now I use Oak. My problem Is when I hit the E-stop button the z-axis drop more than 1.5mm or more. I found that the axis brake has a delay vs the motor driver off.

[attachment=1]report_0008DC111213-0217221262_2022-07-24_12-17-28.txt

[cncsnw]

If you check with PLC Detective or an oscilloscope, you will probably see that OUT9 turns off within 20ms from when you press Emergency Stop; and likely less than that from when the drive enable signal is removed.

The problem is likely that it takes a significant fraction of a second for the brake to mechanically take hold, after the brake coil power is turned off; but the servo drive ceases holding position immediately when the enable is removed.

You could insert some relay logic in the drive interface between Oak and the drive, so that the enable line is forwarded to the drive via an off-delay relay (maintaining the enable to the drive for a few hundred milliseconds after Oak turns the enable off).

You could re-route the drive enable signal to come from an Oak PLC output, and add the off-delay logic in the Centroid PLC program.

You could use Yaskawa Sigma V or Sigma 7 servos, which have a software feature for exactly this purpose (see Pn506 "servo OFF delay time" in the Yaskawa drive manual).

You could contact DMM and see if they have any plans to implement a feature comparable to what Yaskawa does.

[RoblesEng.]

Thanks! CNCSNW for the answer. Im going use the off delay relay.

[aamir]

when press estop the out9 must be off 1st to hold and then servo off .
Servo off logic need to be change by centroid.
I have similar problem i used relay output for servo Enable and made custom logic ,1st brake applied and then 50ms servo off keep in mind work for velocity and position mode only not on torque
Aamir

[RoblesEng.]

Thanks! aamir. Ok, this morning I used the Delta PLC that I use to control the Tool changer, to create a timer delay output and make the off delay relay to control the servo driver but It was not useful , because I only could only mantain the power to the driver not the enable signal. I don't know how to modify the logic of the centroid PLC.

[cncsnw]

To do what you are asking for, you would have to break into the axis interface cable between the Oak axis header and JP4 on the DMM servo drive. That is where the axis enable signal is transmitted: from pin 21 of the Oak header to pin 15 of DMM's JP4.

You would have to make your external PLC read the enable request from the Oak, and set the enable command to the DMM ("set" means close it to 0VDC) when Oak requests it; and then keep the DMM enable command active (closed to 0VDC) for some additional time after Oak turns off its enable request.

[RoblesEng.]

To do what you are asking for, you would have to break into the axis interface cable between the Oak axis header and JP4 on the DMM servo drive. That is where the axis enable signal is transmitted: from pin 21 of the Oak header to pin 15 of DMM's JP4.

You would have to make your external PLC read the enable request from the Oak, and set the enable command to the DMM ("set" means close it to 0VDC) when Oak requests it; and then keep the DMM enable command active (closed to 0VDC) for some additional time after Oak turns off its enable request.

Im working on it, Thanks!!!

[ruirosa]

Hello All
I am installing a OAK board with 3 DMM servos, one of them with brake (Z axis) On a Mikron WF 31D. All the cables were purchased either from Centroid or from DMM.
Having 4 main problems:
1. The DRO does not shows values on the Main screen and several others, only on the MDI Screen can not solve this issue.

2. The mm/rev and software limits are setted following the software limits definition procedure from the users manual. The problem is that the machine does not “respect” them when joging, or moving with a MDI instruction.

3. One of the x limits is a inductive sensor, with 3 wires, how can I wire it to the OAK board?

4. The Z axis with brake (DMM 18 KW) is always falling to the –Z hard limit. When we press the reset, when the E-stop is pressed, when the oak board is disconnected, when we restart CNC12 etc, I followed the DMM and the OAK wiring schematics that are similar and is not working.
Installed a dedicated power unit DC and raised the voltage to 28 vDC instead of the 24 vDC used at the rest of the logic. But nothing seems to work in a way that the brake retains the Z position.

I am uploading 3 pictures as well the report, generated this afternoon.

Help would be very welcome since I am for over a week trying to solve this issues without results.

[cncsnw]

The DRO will show values only after machine home is set.

The software travel limits will be enforced only after machine home is set.

You have used Ctrl-Alt-f, on the Alt-i display, to force OUT9 "ZBrakeRelease_O" to be on all the time. You have to un-force it before it will work properly. To do that, move the highlight box to OUT9 and press Ctrl-Alt-f twice more, so that the white underline disappears.

You are also forcing OUT1 on. That suggests that you have Fault conditions that you have not yet fixed. Your control will not run correctly until you actually fix the fault conditions. Forcing OUT1 is not a substitute.

[ruirosa]

Hello again
Many thanks for your help.
The forced outup 1 is the X axis limit swich, that is a 3 wire inductive sensor, wich I do not know how to connect it to the OAK board.
If possible let me knowhow can I do it.
Regards