Okuma OSP 5020L Alarm 205-3 X Axis

[Mark Pelnar]

Getting alarm listed above on a LNC 8 Cadet with 5020L.
First worked out potential temp problems not an issue here. So we have an encoder issue or a SVP Board issue? Is there a screen to look at encoder data? Is there somplace to see raw encoder data? I keep hearing about how industructiable Okuma encoders are so do I need to be looking at the SVP Board?

[Algirdas]

generally, You can swich SVC boards, You'll see if the one is broken. Can You post full alarm message, please?
Does this alarm occurs during axis movement?

[Mark Pelnar]

The full alarm is "205-3 Alarm A APA Pattern Data X Axis ****" the number changes. This occurs during movemant of either axis or when machine is idle. Watching data, RDIF, RAPA & RCON seems to indicate the X & Y encoders are doing the same thing. We changed out SVP Boards and had the same issue. Finally had a chance to change out Encoder but now we have lost machine zero and I am not finding where to set that in our manuals. So now we are completly down. Waiting on tech to call us back sometimes it takes a while. Any dirrection would be apperciated.

[Algirdas]

obviously, You didn't spared parameters before.
Don't change Y axis position. (most likely, You just mixed with Z). Z You can move, no problem.
1. You need to see, if encoder zero is in encoder range.
2. if present coordinate is in between of system travel limits.
3. setting the new machine zerro.
detailed:
1. Okuma absolute encoders have limits. They are 16m, 2xm and somewhere about 40m encoders. You need ensure, that endocer limit is far away from travel limits when installing the encoder. Don't forget this at the end of adjustment, when You will have full travel range available.
2. if You can move the axis with pulse handle, and axis movement changes direction when You reverse rotation of pulse handle, You're lucky.
3. since you didn't saved Your parameters, the only mark of coordinate is hardware limit switch. There is X axis zero also, but later. First, You make software limits equal to system parameter limits (it's done by adding 0 to corresponding axis system limit value). Next, You allow overtravel through limit switch.
Next You move axis on the limit switch until it acts (look at check data).
Then You go by (5 ... 8)mm away and here You have Your present limit value. Compare it with value, which is recorded as system limit now and calculate necessary encoder offset. Switch off overtravel release.
The axis position will be recovered with accuracy of (2 ... 5)mm that way.
You need to adjust accurate X axis zerro by matching the chuck rotation center with precise tool holder center at certain turret position.
This turret position is the one where You install smallest diameter drill bit. Check where X axis goes when commanded to zerro and adjust machine zerro offset properly.
Don't forget to set user limits and to check if encoder data value doesn't overtravels it's zero in the full range of axis travel
The alarm indicates, the error of encoder pattern, maybe encoder is still good, only adjustments needed.

[Mark Pelnar]

The encoder that was exchanged was off of a machine of the same X travel so I assumed it would be close. I will insure there is correct travel in the limit.

We have the parameter set saved, but when changing the encoder the x value went to -64.000". Because of this we are only able to move +. Do I remove the encoder and manually change the position of the encoder to get us out of the -64.000 range and closer to where we need to be? I am assuming there is more at work in this encoder than optical disc & photo detectors. Is there a physical indicating device, pot or something similar?

[OkumaWiz]

You can "adjust" the encoder number by going to your system parameters and using the PR ZERO OFFSET number. By doing this it is possible to get your X axis zero offset to read exactly the number that is written down in the back of your machine on the Data Management card when the turret has a boring bar holder at spindle centerline. This will give you a "power on effective parameter set" alarm every time you change it and you will need to reboot in oder for the number to be effective. If you do this, you will not need to re-establish where your stroke end limits are since they are based on X-zero and a corresponding distance to the stroke end limit.

Procedure:

if possible park your turret at a known location such as X 0.0000.

1. Install new encoder.
2. Look at the actual position of the x-axis. If it is off by 64.3390 inches, put that number into the PR ZERO OFFSET for the X-axis. (If it says overflow, you will need to add 40 inches to the PR ZERO OFFSET until you get a number within it's travel range.)
3. Backup the parameters (old machines - wait 2.5 minutes, newer, use backup key, latest (p series) just power off.)
4. Re-boot the machine.
5. Look at actual position again to see if your are where you think you should be, if not, re-adjust the PR ZERO OFFSET number again. This may take a few attempts since the encoder uses a pulse count much smaller than your positioning readout. (new encoders are reading out at least 6 decimal places)
6. Once your zero is established back to the original number when at zero, your stroke end limits will drop in like Flynn. You will not need to adjust your zero set, your stroke end limits or your variable limits. They will all be correct like magic.

Yes PR ZERO OFFSET is your friend! I have heard that Okuma is teaching people not to touch it, but this is what it was designed for. This way if you have your zero sets saved in all of your programs, you can get the numbers back to the originals after an encode swap without having to change all of your programs.

Happy offsetting!

[Mark Pelnar]

Thanks to all for your help. We are currently running but I have seen that before also. Using the PR Zero Offset is what I found in the manual to set the encoder and to have that confirmed by OkumaWiz was just the help I needed. Just hate punching numbers into system parameters without confirmation. Hopefully this will take care of this error.

Thanks Again,

Mark

[MCR-B II]

Or when out of range. To adjust we use Zero offset and stroke and limit parameter method. I dont touch PR ZERO OFFSET. You mean that DATA MANAGMENT CARD records stays same.