- Joined
- Sep 8, 2023
- Messages
- 83
Howdy! Now that my lathe and all the accessories are on the way (ETA Jan\Feb 2024) I'm starting to plan and source parts for the 3-phase conversion. As a result, I have been reverse engineering the OEM controls from pictures and threads from this forum. I think I have all the normal controls figured out, but I'm unsure on the following.
1. The foot brake. Is this operating the same was the e-stop circuit is killing power to the 24VAC controls? It's not shown in the manual like everything else is.
2. The gear cover interlock? I'm assuming it's using the e-stop circuit as well?
3. Proximity stops. It appears the most common method is to add a relay that kills power to the forward\reverse controls? Am I reading that correct?
I'm going a bit of a weird route with a Programmable Logic Controller. I know it's overkill and unconventional, but it will be fun and it will be far easier to wrap my mind around software logic rather than the relay logic. I am switching from physical relay logic to software controlled logic, but PLC runs pretty much every manufacturing plant in the world. In theory it should be extremely reliable?
I do plan to wire the e-stop to a physical "safety relay" that will control a contactor to kill 3-phase power to the motor. I'm not sure if there is a better way, but from how I'm seeing it that should be the surefire method and then I can still allow the VFD\PLC logic to brake the lathe. I've had relays and contactors get "stuck" on me, so they are not infallible either.
I am thinking I can do the proximity stop in PLC without concern. The operating time of a relay is milliseconds, and a PLC would be able to scan the entire logic code in microseconds.
I haven't purchased anything but the VFD up to now, but PLC doesn't seem like a dumb way to go? Or is it?
1. The foot brake. Is this operating the same was the e-stop circuit is killing power to the 24VAC controls? It's not shown in the manual like everything else is.
2. The gear cover interlock? I'm assuming it's using the e-stop circuit as well?
3. Proximity stops. It appears the most common method is to add a relay that kills power to the forward\reverse controls? Am I reading that correct?
I'm going a bit of a weird route with a Programmable Logic Controller. I know it's overkill and unconventional, but it will be fun and it will be far easier to wrap my mind around software logic rather than the relay logic. I am switching from physical relay logic to software controlled logic, but PLC runs pretty much every manufacturing plant in the world. In theory it should be extremely reliable?
I do plan to wire the e-stop to a physical "safety relay" that will control a contactor to kill 3-phase power to the motor. I'm not sure if there is a better way, but from how I'm seeing it that should be the surefire method and then I can still allow the VFD\PLC logic to brake the lathe. I've had relays and contactors get "stuck" on me, so they are not infallible either.
I am thinking I can do the proximity stop in PLC without concern. The operating time of a relay is milliseconds, and a PLC would be able to scan the entire logic code in microseconds.
I haven't purchased anything but the VFD up to now, but PLC doesn't seem like a dumb way to go? Or is it?
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