[Pyretta-Blaze]

Hi everyone.

I have the same problem with my machining center. It has a Fanuc 0m control and the 401 servo alarm (VRDY OFF) message comes right at machine startup. I just bought the machine and the seller said there was no alarms before they disconnected the hydraulic unit. After they reconnected the hyd unit, the message appeared. He said that it's probably because theres air in the oil system but I doubt it. Besides I have let all the air out of the oil tubes.

The machine starts normally but after a few seconds a relay clicks and this message appears. I measured some voltages from the power unit module and found out that the module does not have power because the main relay does not work, uknow the really big one right after the main power switch and transformer that is driven by the power unit itself. I manually pressed the relay so that all the modules had power but it had no effect whatsoever. The same 401 message appears.

The servo- or the spindle driver's alarm leds are not lid, but the spindle driver has been changed to a re-built one so im not 100% sure if theres some compatibility problems. But the driver is not broken, it is guaranteed, and there was no alarm when the driver was changed, it appeard later.

Also no axis limits are pressed because none of the axis are close to the ends and I can hear a relay click by pressing emergency button, and the electric charts say the limit switches are serial connected to the emergency button.

Any ideas, anyone?

[CNCZILLA]

Hello. I don't know your particular machine but i can tell you that the VRDY alarm means you dont have the 300 volts on the buss power for the drives. The buss power is the large shinny chrome bars that connect between the drives. Your drives are powered by a power supply. Check your power supply for proper voltages in and out and see if you have a power boot up sequence in your manuals so you will know in what order and when things are powered up in the start up sequence.

[Pyretta-Blaze]

There are full voltage at the power buss when the main relay is manually pressed. But the relay does not connect by itself. But although there are power at all drives, the alarm still appears.

[Pyretta-Blaze]

Still having the same problem... A couple of professionals have had a look at the machine but so far no progress.

I've studied the ladder diagrams and tried to find something that would cause the power module not to connect the main relay. So far I've discovered that all the axis limit switches do work but none of them are pressed, spindle gearbox switches work, emergency button works, spindle and gearbox lubrication works, hydraulics work...

What I would like to know is that does the power module get some kind of information from spindle or axis amplifiers so that this unleading main relay could be a result of some kind of accessory failure or some other fault? If not, the power module has got to be broken because the only input that it gets via a separate cable is the one from emergency button. And i've measured that it works fine.

[ben_heinman]

Improper grounding can also cause this problem. Does this machine have it's own seperate ground or is it grounded with other machines?

[Pyretta-Blaze]

It has its own ground, it is connected to the main grid via a 5-wire cable, 3 phases, zero and a ground. Also the phases are in correct order, and just in case I've tried to run the machine also with reversed phase order.