Setup Z axis brake

[MRW]

Hi there, I am trying to install a z axis brake on my mill. but when I wire to the oak board as per instructions nothing happens. It appears like there is no signal to the board relay as it just stays in the normally closed state when the drive is activated. Can someone please explain how to change this? All it needs to do is open the axis brake when everything is satisfied and close it on an E-stop etc,

Let me know,

[DannyB]

Hey,
I use a zaxis brake with oak, happy to help you figure it out.
Need all the stuff talked about here - pictures, report, etc.

As a quick note, you can see the state of the board input/output by pushing alt-i on the main screen,
You can see if the brake relay output changes state when you try to jog the z axis using the vcp

[MRW]

Ok thanks,

Attached you will find the report. As far as pictures I am not sure what to take a picture of. I had the brake hooked up to the output 9 on the oak board but that relay does not do anything it seems to be dead. I hooked an ohms meter to it to see if it would change from NC to NO but nothing happens so I am thinking that there is some perimeter or setting that is not correct. For now I wired the brake through the E-stop circuit which works to a point. At least I can move the axis. The only issue is that if the E-stop is cycled the brake comes on as it should but when You release e-stop there is to much delay for the drive to come on and hold the axis that it ends up falling, so something needs to change.

[cncsnw]

Your PLC program does not contain any definition or logic for a Z axis brake.

First, you will want to change:

Code: Select all

;spare                        IS OUT9  ;SPDT Type

to something like:

Code: Select all

ZBrakeRelease                   IS OUT9  ;SPDT Type

Then, typically somewhere in MainStage, add code to activate that output.

If you are using Yaskawa servo drives, then you can use something like:

Code: Select all

; Release Z axis holding brake when drive says to, via Oak interface
IF !Axis3StatusBRAKE THEN (ZBrakeRelease)

I think that will work with Delta servos as well.

With any other drives, you probably have to use something like this instead:

Code: Select all

; Release Z axis holding brake when CNC11/CNC12 or MPU11 says axis is enabled
IF SV_PC_POWER_AXIS_3 THEN (ZBrakeRelease)

That is less desirable, as it precludes using test and tuning features that are built into the servo drives.

[tblough]

On the input screen (Alt-I), can you force output 9 on using CTRL-ALT-F with ouput 9 selected? Each tap of CTRL-ALT-F should cycle through normal, forced on, forced off. That will verify the output works. Then you need to add the PLC code pointed out by CNCSNW.

[MRW]

Your PLC program does not contain any definition or logic for a Z axis brake.

First, you will want to change:

Code: Select all

;spare                        IS OUT9  ;SPDT Type

to something like:

Code: Select all

ZBrakeRelease                   IS OUT9  ;SPDT Type

Then, typically somewhere in MainStage, add code to activate that output.

If you are using Yaskawa servo drives, then you can use something like:

Code: Select all

; Release Z axis holding brake when drive says to, via Oak interface
IF !Axis3StatusBRAKE THEN (ZBrakeRelease)

I think that will work with Delta servos as well.

With any other drives, you probably have to use something like this instead:

Code: Select all

; Release Z axis holding brake when CNC11/CNC12 or MPU11 says axis is enabled
IF SV_PC_POWER_AXIS_3 THEN (ZBrakeRelease)

That is less desirable, as it precludes using test and tuning features that are built into the servo drives.

Where do I insert these?? I have Estun drives.

[cncsnw]

You insert it in your PLC program source file. Then you compile the source file to make a new mpu.plc file. Then you restart the control.

The PLC program source file you have been using is named "Centroid-Mill-Standard-OAK-ATC-Umbrella-r2.src" (though I am not sure why you would need an ATC program if you do not have a PLCADD1616 board and an automatic tool changer).

For a general idea of the process of identifying, editing, and compiling your PLC program source file, see viewtopic.php?f=60&t=1141

For more information about PLC programming in general, see:
http://www.centroidcnc.com/centroid_diy ... manual.pdf

[DannyB]

Your PLC program does not contain any definition or logic for a Z axis brake.

Looks like it was left out of the ATC programs, the non-ATC ones have it defined properly

[DannyB]

You insert it in your PLC program source file. Then you compile the source file to make a new mpu.plc file. Then you restart the control.

The PLC program source file you have been using is named "Centroid-Mill-Standard-OAK-ATC-Umbrella-r2.src" (though I am not sure why you would need an ATC program if you do not have a PLCADD1616 board and an automatic tool changer).

Just to +1 this - if you don't need the ATC functionality, the standard OAK plc program already has the zbrake defined properly.


Otherwise, following the directions, add

Code: Select all

 IF SV_AXIS_VALID_3 && SV_PC_POWER_AXIS_3 && Axis3DriveOk
   THEN (ZBrakeRelease)

(This is the code the standard program uses)

below

Code: Select all

 IF SV_AXIS_VALID_4 && SV_PC_POWER_AXIS_4 && !Axis4DriveOk
   THEN FaultMsg_W = AXIS4_DRIVE_FAULT, ; 7169(1+256*28)
     SET AxisFault_M,
     SET Axis4Fault_M
 

that already exists.

Place

Code: Select all

 ZBrakeRelease                 IS OUT9  ;SPDT Type

below

Code: Select all

 SpindleDirectionOut           IS OUT8  ;SPDT Type

that already exists.

[MRW]

Ok thanks I will look into this further.
This machine does have a add1616 board and does have a ATC.

Hopefully I can figure this out.