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Petros cnc machine tool's blog

Connecting RS232 cable to machine locks control up

This was the most interesting CNC problem of the year!  Had a customer with a Brother TC32B CNC machine that has had a problem from day one when they got the machine. What happens is when they connect the RS232 cable to the main NC Board the machine locks up. No alarms, screens change but cannot handwheel or perform any physical movements. The machine could communicate via RS232 with the cable connected. They tried a new computer as well as a cable but the same thing occurred. First though was the NC board must be bad, but the customer had already replaced it.

CNC control locks up during booting on GV-503 with Exception Error 0005E CPPOM30 Alarm 3 on NC

Customer had this problem occur one morning when powering on the machine. The CNC control locked up during Booting with Exception Error 0005E CPPOM30 Alarm 3 on the Main NC unit. The machine was a on GV-503 with a meldas CNC control

X-axis stops moving during machining cycle with no alarms

Troubleshooting problems when no alarms occur are always fun. In this case it was an intermittent problem where I happen to get it to stay in a condition to troubleshoot. The main goal of any troubleshooting is to repeat the problem or troubleshoot when it is in the current fault condition. With this problem I was lucky to have the problem occur and catch it in time before it changed back.

Hydraulic pump kicks out during operation - CNC


Feedrate Slows Down for No Reason During Machining

Had this problem occur on a machine where the customer was milling across a long part. During the machining process the feedrate slows down and speeds up constantly. After troubleshooting the feedrate problem I determined that the spindle speed was slowing down as well. When the spindle speed slows down the feedrate automatically comps to maintain the recommended rate of removal and changing with the spindle speed.

Spindle orientation troubleshooting on older fanuc controls

If the RS232 port does not work any more.

What if the RS232 port is bad or not working on your Fanuc control?

Recieved this from a Member of for if you have a bad RS232 Port on a main board or some fanuc controls. Since most fanucs have two ports you can just swap the plug to the other port that is not being used and have a fully functional RS232 port. Then use a different channel for setting your RS232 settings. Wish I would have known this years ago or thought of it.

Fanuc Powermate F alarm 090 224 on machine power up.

A Fanuc Powermate F alarm 090 224 occurred on a customers machine at power up. Had tried to walk him through resetting the powermate home position several times but the original procedure would not work. The 090 and 224 alarm indicates a lost home position. However batteries were ok and they were replaced as a precaution. The problem was that it was impossible to reset the home position and it would not take. Fanuc Powermate drives often are stubborn from my experience when setting there home positions.

301 B axis communication error on fanuc control

301 B axis communication error came up on a fanuc controlled machine that had scales for the B- axis or rotation of table. After troubleshooting everything and getting down to that it had to be the scale. Ordered a new scale and tried it. Unfortunitly the same alarm occured. After looking into the parameters I was able to tell that someone had turned off the scale at one time because all the paramters had told me so except for one. Parameter 1815 bit 1, bit4, and bit 5 were all 1's.

Soft overtravel limit alarms when Zero returning alarms - 500 & 501(soft over travel)

All to often I get phone support calls for soft overtravel alarms on fanuc controls. The soft overtravel limit alarms typically occur after a power outage, hitting an overtravel, or crashing a machine. Many times it is an Alarm 500 nth Axis stroke limit + or 501 nth Axis stroke limit  on the newer fanuc controls 16/18/21.

Definition of a softovertravel or soft over travel limit alarm.

Hitachi alarm- " can't cycle start Auto operation

Today had an alarm on a Hitachi VN40II " can't cycle start Auto operation "

Spindle speed bogs down while cutting

I was working an Emag CNC machine the other day. The customer was having problems when they were boring into the part. The spindle would bog down during the cut. When viewing the Spindle actual RPM compared to the commanded spindle speed the actual would decrease to about 1200 from 3000rpm. To try to determine the problem I had a few things I checked first. The tool ins

Tool clamp signal going off during cycle on Mori seiki MH1000

Had a good problem that I chased my tail on the other week.  When the program was running occasionally the machine would alarm out with "tool not clamped". The machine was a Mori Seiki MH1000. I checked the typical prox switch on the back of the unclamp cylinder to make sure it was back which is the only clamp confirmation signal for this machine. I was able to see that it was not back all the way one time during the process. I tried taking a pry bar and to pull the cylinder back and it moved about a 1/8 inch.

Alarm on Hitachi can be tripped by breaker only, but breaker was not tripped.


Hitachi Generic alarm generated.

The alarm that was being generated had no description at all. On this particular Hitachi machine tool you must look at the diagnostic addresses on the Fanuc side which will tell you the alarmed bit. On this machine I had an alarm that could only be generated from a breaker trip circuit according to the electrical prints. However when the alarm occurred the breaker did not trip. I looked at what was in this breakers circuit and found that it was for multiple things. Air cooler exchange fans, cabinet fans, machine light and several other things.

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