Search found 692 matches

by Richards
Wed Mar 27, 2024 1:53 pm
Forum: Centroid Acorn CNC Controller
Topic: Need a small motor for lathe spindle
Replies: 2
Views: 75

Re: Need a small motor for lathe spindle

I've used Teknic's ASU-FR510 unit to control an MCPV motor from 0-10VDC. The ASU-FR510 costs about $60.
by Richards
Thu Feb 08, 2024 7:54 am
Forum: Centroid Acorn CNC Controller
Topic: Proximity Sensor issue, never trips? < solved, used NPN>
Replies: 8
Views: 573

Re: Proximity Sensor issue, never trips? < solved, used NPN>

Maybe if I drawn the circuit as a generic snubber, you'll see that the diode is not shorted. In the circuit, current passes through the resistor, through the coil, and then through the NPN transistor. The diode suppresses induced current when the transistor is turned off by shunting that current bac...
by Richards
Wed Feb 07, 2024 4:54 pm
Forum: Centroid Acorn CNC Controller
Topic: Proximity Sensor issue, never trips? < solved, used NPN>
Replies: 8
Views: 573

Re: Proximity Sensor issue, never trips? < solved, used NPN>

KB58, no offense taken. However, did you notice that the In4148 is reversed biased, which is the correct orientation for its use as a shunt to protect an Acorn Input. The Acorn input is basically an opto-coupler. The Anode of the opto-coupler is connected to +24VDC internally. The Cathode of the opt...
by Richards
Mon Feb 05, 2024 9:52 am
Forum: Centroid Acorn CNC Controller
Topic: Proximity Sensor issue, never trips? < solved, used NPN>
Replies: 8
Views: 573

Re: Proximity Sensor issue, never trips?

Mistakes happen. Years ago, I bought some PNP prox. sensors instead of NPN sensors. That was before parts were available in two days on the Internet. I wasn't uncommon to have to wait for weeks for parts to arrive, unless you were willing to pay expense rush fees. Instead of spending $100 for three ...
by Richards
Sun Jan 14, 2024 7:22 pm
Forum: Centroid Acorn CNC Controller
Topic: Leakage Circuit Breaker Question
Replies: 5
Views: 659

Re: Leakage Circuit Breaker Question

Google Earth-leakage circuit breaker. By definition, they are not exactly the same as a GFI breaker. A Wikipedia article described two types, ELCB (voltage) and RCCB (current). Since you're the designer/engineer on your project, you can do anything that you want; but, if I were using your components...
by Richards
Sun Dec 24, 2023 12:25 pm
Forum: Centroid Acorn CNC Controller
Topic: In over my head - New CNC Router rebuild.
Replies: 46
Views: 17132

Re: In over my head - New CNC Router rebuild.

One of my favorite physicists is Richard Feynman because he explained complex things simply. His goal was to convey knowledge so that whoever was listening would understand both the problem and the solution. With Feynman's approach in mind, connecting a stepper motor driver to the acorn is simple. 1...
by Richards
Tue Aug 08, 2023 6:03 pm
Forum: Centroid Acorn CNC Controller
Topic: HomeAll Tripped on board without tripping switches
Replies: 3
Views: 442

Re: HomeAll Tripped on board without tripping switches

You stated that the LED is GREEN. Wouldn't that indicate NOT tripped? RED would indicate tripped. Noise can cause a false signal. You can reduce noise by adding a resistor to the input. You could use a 1/2W 4,700 ohm resistor. Connect one end of the resistor to 24VDC. Connect the other end to the IN...
by Richards
Mon Jul 24, 2023 7:29 am
Forum: Centroid Acorn CNC Controller
Topic: Mist coolant wiring 24vdc
Replies: 13
Views: 1293

Re: Mist coolant wiring 24vdc

Here's a simple schematic that might help. L1 is the solenoid. D1 is a diode (1N4002 - 1N4007). SW1 is the relay module on the relay board. When the relay is turned ON, power flows through the solenoid. When the relay is turned OFF, induced voltage (surge) is shunted back through the diode to the po...
by Richards
Sun Jul 23, 2023 10:10 am
Forum: Centroid Acorn CNC Controller
Topic: Mist coolant wiring 24vdc
Replies: 13
Views: 1293

Re: Mist coolant wiring 24vdc

The first step in using an unknown solenoid (or any other device) is to understand how it works. You said that the solenoid is 24VDC N/C. Hook it up to 24VDC through a simple toggle switch. See what the solenoid does when power is applied and when power is disconnected. Each relay on the relay board...
by Richards
Mon Jul 10, 2023 3:44 pm
Forum: Centroid Acorn CNC Controller
Topic: Common, -VDC, Chassis Ground?
Replies: 10
Views: 1003

Re: Common, -VDC, Chassis Ground?

Usually that will work; however, there is one problem. DC supplies are usually mislabeled. A 24VDC supply is usually labeled +V and -V where +V = +24VDC and -V = 0VDC. If you buy a power supply that has a negative DC voltage, be sure that you know which terminal is 0V. That terminal should be connec...