Fanuc 6t coordinate hacks

[Capybara_Forest]

Hoping this is the correct thread, but does anyone know if there's a method accurate enough, a better hardware or macro solution I could try to avoid resetting coordinates every time I power on the machine? My setup is a Nissin NST40/150 2-axis lathe with a FANUC 6T/B controller, and homing it daily with G28 U0 W0 feels a bit tedious. One idea I had was to note down the X- and Z-coordinates at home position and re-entering them the next day with G50. Let me know y'all think.

 

[clowninabox]

Have you cheked the battery? Because dead or weak battery can make the machine lose the coordinates. Therefore, you'll have to replace the backup battery or replace it with a higher capacitor capacity.

 

[Capybara_Forest]

Have you cheked the battery? Because dead or weak battery can make the machine lose the coordinates. Therefore, you'll have to replace the backup battery or replace it with a higher capacitor capacity.

Ah that makes sense, I hadn't even thought about the backup battery playing a role here. Do you know if there's a way to check its condition without pulling the whole thing apart?

 

[IVGrbn]

Hoping this is the correct thread, but does anyone know if there's a method accurate enough, a better hardware or macro solution I could try to avoid resetting coordinates every time I power on the machine? My setup is a Nissin NST40/150 2-axis lathe with a FANUC 6T/B controller, and homing it daily with G28 U0 W0 feels a bit tedious. One idea I had was to note down the X- and Z-coordinates at home position and re-entering them the next day with G50. Let me know y'all think.

Using G50 for homing on a FANUC 6T/B isn't reliable. G50 sets a temporary work coordinate system or maximum RPM, it doesn't store a permanent absolute home position. For consistent homing, use the machine's reference return G28. If your machine loses its home position after powering off, the absolute pulse coders or their battery backup are likely failing, like @clowninabox suggested. FANUC 6T/B systems use pulse encoders, and for the machine to remember its position, it needs a battery to keep the encoder data alive when power is off. I'd highly recommend checking the battery on your control. If it's weak or dead, replacing it is the first step. This usually requires a specific Fanuc battery. But if the battery is good, then it could be an issue with the absolute pulse coder itself or the associated wiring. If they're faulty, the machine will lose its reference.

 

[Capybara_Forest]

Using G50 for homing on a FANUC 6T/B isn't reliable. G50 sets a temporary work coordinate system or maximum RPM, it doesn't store a permanent absolute home position. For consistent homing, use the machine's reference return G28. If your machine loses its home position after powering off, the absolute pulse coders or their battery backup are likely failing, like @clowninabox suggested. FANUC 6T/B systems use pulse encoders, and for the machine to remember its position, it needs a battery to keep the encoder data alive when power is off. I'd highly recommend checking the battery on your control. If it's weak or dead, replacing it is the first step. This usually requires a specific Fanuc battery. But if the battery is good, then it could be an issue with the absolute pulse coder itself or the associated wiring. If they're faulty, the machine will lose its reference.

Thanks for the detailed explanation. It's clear my G50 idea wasn't the right path, so I'll abandon it.

The battery issue is becoming a common theme. Before I order a replacement, is there a particular part number for the FANUC 6T/B system I should find? Also, can the battery be changed while the control has power to prevent losing any other system parameters?

I likely won't have time to get into the control cabinet until the end of next week, but I'd like to get the part ordered beforehand.

 

[IVGrbn]

Glad to be of help! The part number you're looking for is often A98L-0031-0025, which is a 6-volt lithium battery pack. It might also be listed under a more general type like BR-2/3AGCT4A. You can confirm the exact part number by opening the control cabinet and checking the label on the battery pack currently installed. It's a common one and widely available from Fanuc parts suppliers or online from places like eBay. As for your second question, yes, it's actually crucial to change the battery with the machine powered on. The battery backs up the memory, so if the machine is off, you'll lose all your parameters and offsets. The control has a short-term capacitor to hold memory, so just be ready with the new battery and swap it as quickly as possible. Backing up your parameters first is always a good idea.

 

[mill4nddrill]

That's really useful info, I could definitely use that tip about swapping the battery as well. Keeping the power on while doing the replacement is crucial for maintaining the settings. The A98L-0031-0025 pack is pretty common, so finding one shouldn't be too difficult.

 

[Capybara_Forest]

The details confirmed my plan. The battery (A98L-0031-0025) arrived yesterday. Tonight I'll back up the parameters and swap them tomorrow. This discussion has been immensely helpful, guiding me from a bad idea to a clear, correct solution.

 

[badfish22]

Hoping this is the correct thread, but does anyone know if there's a method accurate enough, a better hardware or macro solution I could try to avoid resetting coordinates every time I power on the machine? My setup is a Nissin NST40/150 2-axis lathe with a FANUC 6T/B controller, and homing it daily with G28 U0 W0 feels a bit tedious. One idea I had was to note down the X- and Z-coordinates at home position and re-entering them the next day with G50. Let me know y'all think.

Make sure your home switches are dead-on, or your G50 could be off. If you're doing close-tolerance work, run a quick test or use a dial indicator to double-check.

 

[LittleTate09]

Glad to be of help! The part number you're looking for is often A98L-0031-0025, which is a 6-volt lithium battery pack. It might also be listed under a more general type like BR-2/3AGCT4A. You can confirm the exact part number by opening the control cabinet and checking the label on the battery pack currently installed. It's a common one and widely available from Fanuc parts suppliers or online from places like eBay. As for your second question, yes, it's actually crucial to change the battery with the machine powered on. The battery backs up the memory, so if the machine is off, you'll lose all your parameters and offsets. The control has a short-term capacitor to hold memory, so just be ready with the new battery and swap it as quickly as possible. Backing up your parameters first is always a good idea.

Thanks for the info! When swapping the battery with the power on, is there any risk of shorting something if I'm not super careful? Also, for backing up parameters, is there a simple way to do that without special software?

 

[Capybara_Forest]

Just posting a final update on the situation. The battery swap I did over a week ago was a complete success. For anyone else attempting a live swap, the battery connector was well insulated which made the process feel safe. I ended up just taking clear photos of all the parameter screens with my phone for a backup. The machine has held its coordinates through multiple power cycles since the repair.