siemens micromaster 440 VFD resets to factory defaults in voltage loss

[jurriaan]

I have a Siemens Micromaster 440 VFD device, that unfortunately forgets its settings on input power loss . On a computer, I would replace the BIOS battery. Could anybody tell me where I should start to look on this device?

Thanks!

 

[ozmosis]

For a start, it shouldn't be doing this. My first instinct is that you have a problem.
All paramter values other than read-only values should be stored in EEPROM.
There is a parameter (P0014) called store mode but this just determines between RAM and EEPROM for all settings, I recall. The default should be 0 (it's a level 3 parameter so you need access to all paramters P0003=3).
It really does sound like you have a problem but this could be caused by EMC intereference onto the control card.
Many years ago with the MM2 and MM3 it was a problem (it was known as the Alzhiemer bug) but not to my knowledge with the MM4 range.

As it is doing a factory reset anyway maybe do a full factory reset and carry out correct commissioning as per the manual ensuring all actions in P0010 are carried out correctly to 'finish off commissioning' otherwise the drive might still think it is in commissioning mode and not be 'ready to work'.

 

[jurriaan]

I did reset to factory settings before programming the unit (not that my programming was all that much, I set the parameters for commissioning after P0010, then P1236 for compound braking, P1300 to vector control without sensor and P2000 to the maximum frequency I entered during commissioning).

However, I just looked up the value of P0014, which according to my parameter list, is 1 for 'store in RAM' and 0 for 'store in EEPROM'. It was set at 1. So I reset it to 0, programmed the VFD again, pulled the plug and it then again reverted to factory default settings, including, ironically, P0014 at 1. I hope I didn't buy a dud!

 

[ozmosis]

Odd; according to all my documents P0014 factory default is 0.
When you carry out a factory reset, do you set:
P0010=30
P0970=1
?
remove all Digital inputs (incase you are getting EMI through these-I've known the thermistor connection going into a motor to be a real bad source of EMI into the control board and can sometimes corrupt the eeprom.)
Try that.
Firstly though, has it ever worked properly or is the first time you have tried it?
If it's worked ok before-has anything changed?

Another point. When you lose power, how quickly does it return? A quick switch off and on can sometimes confuse the drive.

Finally, it could be a dud. Maybe the eeprom is just tired out. It happens to us all...

 

[PolyMike]

Jurriaan, did you set P0971=1 after the converter commisioning?

How did you carry out the converter commisioning? I had similar trouble using the STARTER software. Try to use DriveMonitor or set the parameters one by one with the BOP.

 

[jurriaan]

Ozmosis: I did to a P0010=30, P0970=1 as per the manual. I'm using a simple motor without thermistor, basically just a controlbox with on/off, left/right and a potentiometer for the speed.

As for has it worked before: it was sold as 'in working order' on ebay. It's a risk I took, I know. Losing power means pulling the plug and coming back to the VFD in the morning.

PolyMike: I tried a factory reset, followed by commissioning with the BOP, then P0971=1, but the symptoms remain - it goes back to it's default settings after losing power.

One non-standard thing about this VFD was that it came with a profibus module attached (which I've since sold off separately). I've had a VFD with a profibus module from the same seller before, however, which worked fine with a BOP installed. After buying this one, I gave it a quick test (does it turn the motor? OK!) and continued with home renovation. Now that my new windows are installed, I have time to return to this.

The other thing is that it seems to me this unit takes a long time to powerup - it displays a '----' pattern on screen for easily 30 seconds, I've never noticed that on other 440 VFD's. I'm tempted to guess during that time, it's rewriting it's settings, but I don't know why it would do that.

Thanks for the hints so far. I do hope you know even more!

 

[jurriaan]

Another observation: when I pull the plug, not all parameters revert to the factory default settings, for example P1120/P1121 (spinup/spindown time) keep my settings. Some essentials like P100 (eur/usa values), P304/P305 (voltage/amperage of the motor) don't keep their settings, however, and that prevents me from using the VFD productively.

 

[jurriaan]

I've found out what was happening:

there's a dip-switch to put the device in USA (HP, 60 Hz) or Europe (kW, 50 Hz) mode. There's also a setting to indicate that mode (P100). If P100 says Europe, but thedip-switch says USA, on boot-up, the dip-switch wins and the VFD spends quite some time switching all the settings it thinks depends on those settings to their defaults, including things like P304/P305 and also P100 itself. Some settings remain the same, but a lot of important settings wander back to their default values.

Since then I've made sure the dip-switch and P100 agree on where the VFD is, and now all is just fine - it boots up a lot faster and remembers it parametrization.

Thanks for the tips,
Jurriaan