FANUC 21i-MA Alpha Series 401 error and addtl. info

[tcom-frazzled]

Folks,

I'm coming up to speed on FANUC controls as I'm setting up a CNC router that i recently purchased. In the process of moving it, one of the servo encoder cables had an end get damaged. This isn't a huge deal, as I have already ordered the replacement ends and can fix the problem as soon as they get here. I am trying to get as much of the machine setup and testing done as I can this weekend, so here is where I'm at:

I have 230v 3 phase power to the machine cabinet (phase converter with a delta-wye isolation transformer). I have verified all phase to phase voltages and each phase to neutral. Phase to phase is 227-230 for all 3, well within balance tolerances.

The NC powers up and I have verified the 24v bus voltage in the system, measures 24.09 volts.

The machine is equipped with a 3 axis, alpha series servo amp. I have the X(U) and Z(W) servos connected. The Y(V) axis servo is the one with the damaged encoder connector, so it is not currently attached.

I have dummied out the Y axis in the NC parameters (set parameter 2009.DMY to 1 in for the Y axis). Upon doing this, the NC release from Estop proceeds to alarm for zero return on the X and Z axes, which I'm fine with and can correct, but it also is throwing a 401 VRDY OFF alarm for the X axis and Z axis. The PSM and servo amp both show a status of "-", indicating not ready. Release of Estop/reset on the NC does not cause the MCC contactor to close, so the VRDY OFF is not unexpected.

Here is what I'm trying to understand, as I would like to jog the gantry so that I can do some additional mechanical work on the machine while I'm waiting for the connectors to arrive. Will a three axis drive allow me to dummy out a single servo axis like this without the use of a dummy plug being installed for that axis?

If I manually actuate the MCC, the DC bus powers up to 330v, so I'm pretty convinced that the PSM is OK. Is there any way to look at the internal signals to verify the MCON, HRDY, DRDY, etc. signals to further troubleshoot this? going into the PMC status table and searching for them didn't yield any results.

Any additional info would be greatly appreciated!

-Dave

[tcom-frazzled]

So, as I understand it, when the machine exits estop, it should be issuing a PRDY to the drive. Is this PRDY going out what gets passed from the drive to the PSM and tells it to close the MCC, which would then bring the 230/3P into the PSM and provide power to the drive? After which the drive would come online and then send back a DRDY to the NC to let it know that everything is OK and ready for motion?

Nothing I've read in the manuals is really clear about the order of operations on this. In one section is says that a status of "-" means things are waiting for MCON (and PRDY?) from the NC, but in the PSM maintenance guide, it mentions the PSM pulling in the MCC during power-up but doesn't say what the state of the NC has to be in order for this to happen. I've also seen people mention pulling the CX3 (MCC) connector and testing across pins 1 and 3 with an ohm meter, saying that if it is open the PSM is bad. In order to fully evaluate that, wouldn't you need to know what command or condition allows the PSM to decide to close its internal MCC pull-in relay? I'm sure estop is in there, but what other conditions must be met? Does the PSM go to status 0 with just estop cleared and just the servo amp responds to the PRDY to come online, or does the servo amp take the PRDY and pass it on to the PSM, causing MCC to close and they both come online at the same time?

I know there are some really sharp folks on the forum that could help me understand the power up order of operations for the control and drives and I was under the impression that the Fanuc discussion area would be the place to ask. Even if the lack of a Y axis encoder IS the issue, I still think it would be beneficial to know what communications go back and forth during power up and release from estop.

Is this another subject where the information is proprietary and GE Fanuc will strong-arm anyone that shares knowledge of this black magic? Should I be posting under some other area?

[tcom-frazzled]

It would appear that the multi-axis drive will not pull in the MCC unless it has all 3 encoder signals, despite anything you may dummy out in the control. I'm sure it was obvious to someone, but I'm still on the learning end of these controls and the way they work from a machine building perspective.