Can not reset UHU Servo Controller

[mibo1112]

Hello,
I have bought several pcbs from embeddedtronics and build them. I've made simple connections for testing (without shielded cables - just wires). Put the autotransformer for servo motor supply, so that I can continously change the voltage. Try it on 30volt - fine, then 40 -fine, 50 - fine, 60 - not so fine!
I'm using Mach3Turn. Just jogging the axes to see if the boards work. When I jogged in one direction everything was fine, but when I pressed "arrow" to jog in the other direction motor started oscillating, and "ERROR" LED turned on. I tried to "RESET" by pulling reset pin of "ATMEL ATtiny2313" to ground, but can not eliminate "ERROR" LED. Turning ON and OFF the board power supply (12 Volt supply) don't help. Tried it several times, with different time gaps in between...
Is it possible that the MCU went dead because of not shielded cables?
Any suggestion on how to solve the problem?

Thanks,

Milos.

[per.e]

Try to switch the cables to the motor, red - black & black - red.
Hope this help you.

[LZ1TWB]

Have you tried to connect the serial connection to another computer and see if you have a good working controller, maybe change some parameters. If it oscilates you need to change the, P / I / H vars.
What happens when you turn on just the logic PS? Does the error led light then?

Todor

[mibo1112]

Thanks for replays guys,

per.e - I assume You tried to point me in direction of wrong encoder (or motor armature) connection. I had that problem on the start and solved it very quickly, so this is not that. As I mentioned, when I'm using small voltage amounts, everything is fine, but when close to 60volt of motor PS then the problem occurs. I blocked (hope not damaged) two UHU controller chips the same way, and not going to block some more!

Todor - I thought about this suggestion of Yours over the last weekend. It crossed my mind even before I opened this thread, but due to other jobs and duties had not had the time for trying it. I will sure try it. Though, don't know if it would help, cause I can’t hard RESET the chip - by pulling its RESET pin to ground. By Uli Ubers user manual for the chip (downloaded from its website) hard RESET should reset the chip!?
When You said logic PS do You mean just 5V or 12 and 5 Volt together. I tried to disconnect 12 Volt supply of controller board several times, but no success...

Again, thanks for Your replays.

[LZ1TWB]

Hi,

By logic supply I mean the 12V line. The 5V is made onboard from this same 12V. Just don't connect the motor supply. All you need is a serial cable between the board and the computer. When you connect it and power up the board you should see something like this: UHU number ###, EEPROM: OK. If you see it you should not have problems.

What source you use to power the board - voltage, max amps?
I have heard a few people having problems like yours with this kind of PCB, but I am not sure what was the conclusion.

Todor

[mibo1112]

Hi Todor,
Thanks for Your replay.
I've also bought optoisolated board for connection to a PC computer, and this board needs additional 5V supply.
I sure will not connect motor power supply, which would make things pretty ugly. As I finished a faculty of electrical engineering in Belgrade that kind of mistake is not something that could happen.
You asked for 12V. Well, I had no time to build new power supply, didn't have old computer power supply (+12 and +5 volt), but did have a 12V car battery, so I used this.
Still didn't connect servo controller board to a PC, can't find time these days.

Milos.

[H.O]

Hi,
If the Error-LED is ON all the time make sure that you have a logic level high on pin 14 of the UHU-chip. If this pin is not "high" then the chip will enter fault-state.

Make sure you wire it up the PC and terminal program. That way you'll see if it A) runs at all, B) communicates properly and C) if the EEPROM checks out OK and that you can set and save parameters properly.

Though, don't know if it would help, cause I can’t hard RESET the chip - by pulling its RESET pin to ground. By Uli Ubers user manual for the chip (downloaded from its website) hard RESET should reset the chip!?

A "hard reset" will simply restart the chip, restoring any parameters that has not yet been saved, more or less like cycling the power. IF the EEPROM content has been corrupted, which apparently can happen on boards with bad layout etc, a hard reset will NOT restore it. In this case the only possible solution is to use the terminal and re-enter the parameters if the firmware allows that despite it detecting the EEPROM being "faulty", I don't know how it handles it that case.

/Henrik.

[mibo1112]

Hi Henrik,
And thanks for Your replay and suggestions. I'll most likely try these for this weekend - hope that I'll have more free time. Thanks again,

Milos.

[jjobezo]

I have been following this thread because I have had almost the same problem with one out of three boards that I built. My major symptoms are that I get a lot of noise on the encoder signals causing an immediate error. This is with only the logic power on, computer connected and no other connections. I did determine that it seems to work OK at a 9V level but when I get higher like 12V then the problems appear.

Thank you for any suggestions.

[mibo1112]

Hi guys,

Finally find some time to play with boards again. So, you were right. When I made board tests, motor wires were pretty close to other (encoder, optoboard) and this was surly made a problem, cause the wires wasn't shielded.
I connected problematic board, or better to say board with problematic controller yesterday, on a amazing fast PC 486 DX , 66 MHz working computer, with a pure DOS platform, and serv200 terminal program.
So, when I connected the board to computer, and turned the 12V power on, a message ... EEPROM Error!..... appeared. I used "?" and "ENTER" to see a PID parameters, and boy, there was something to see. On one problematic controller (I made two controllers "bad") all parameters were equal zero! So, I changed them, soft reset the controller, and now everything is fine. On other controller, most parameters were fine, but two of them had something like -12254 value. Again, I've changed that, reset, and now it was fine.
So, the problem I had was an EEPROM problem.
Now, that is gone, but there is something else, that I didn't solve yet. Sorry, that is for the other thread. The thread name will be "UHU Chip problems" if somebody is interested.