401 PLC Failure

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Chenfuee
Posts: 1
Joined: Wed Oct 16, 2019 12:57 pm
Acorn CNC Controller: Yes
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401 PLC Failure

Post by Chenfuee »

Im currently operating the Centroid Mill VBM-34 and i keep getting the error message "401 PLC Failure". What is this and what can i do to fix it?
cncsnw
Posts: 3763
Joined: Wed Mar 24, 2010 5:48 pm

Re: 401 PLC Failure

Post by cncsnw »

My guess is that this is a "Venture" bed mill, imported and set up by Machine Tools Direct in the 2002-2004 time frame.

It probably has an M400S control with a SERVO3IO drive/PLC unit (see http://www.cncsnw.com/Drives.htm#SERVO3IO). The control serial number would be in the low 20000's.

The most likely source of your problem is that the micro-ATX power supply on the back side of the SERVO3IO unit in the control cabinet has failed. If there is 120VAC going into it via the PC line cord at the top, but there is not 5VDC and 12VDC coming out (measured at one of the hanging power plugs, 5V from red to black, 12V from yellow to black) then the power supply is dead.

You can replace it with any micro-ATX or SFX computer power supply. You will need to locate the green wire in the ATX power plug (4th from one end), and cut/jump that wire to join it to either adjacent black wire. When you look at the old supply, you will see how and where this was done.

If the problem is not the power supply, then someone or something has probably compromised the fiber optics that run from the CPU board in the console, through the conduit, down to the SERVO3IO unit.
MikeMullaney1320
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CPU10 or CPU7: No

Re: 401 PLC Failure

Post by MikeMullaney1320 »

Similar fix for .. DC310?
cncsnw
Posts: 3763
Joined: Wed Mar 24, 2010 5:48 pm

Re: 401 PLC Failure

Post by cncsnw »

A DC3IO (not "DC310") has the same type of power supply on the back, and is subject to similar failures if it quits.

The DC3IO does have status LEDs, including ones along the bottom edge to indicate whether there is good +5V, +12V and -12V power. Checking those LEDs would be a good place to start.
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