Centroid Community CNC Support Forum

I'm learning new things.

Sawdust Steve wrote: ↑Wed Feb 23, 2022 3:50 pm I'm learning new things.

much better! i can see clearly now..l

With the simplicity of the G540 setup, I have to believe that the issue is with the DB9 wiring. I would verify that you have that wiring correct. Need to ensure that the pairs used are correct for each coil.

good advice from CNCMaryland. I would look there as well.

and have you tried a different DB25 cable?

The builders used square connectors and even the spare steppers have them. I don't want to cut anything yet. I did measure resistance at the connector going into the G540 and they match up with the schematic.
I don't have another DB25 cable readily accessible. I could try getting one off a mach3 machine with G540. Let me see.
Steve.

In order for this to work right:


First, You must have a DB25 WIRED Straight through MALE MALE cable. Are you absolutely sure you have a DB25 straight through cable? Not a modem, not a serial, not a null modem cable.
Second, take the cover off one of the DB8 cables and please take and post a picture of the wiring to the pins. Also what resistor value did you use for current limiting and how did you get that value?
Tell me what color wires to which pin number you have wired on the DB9
Also, what is the model number of the Stepper motor on the machine? Are there any numbers on it? Do you have a spec sheet on the motors you can post?

The fact that the motor rotors are not locking on G540 Power up, indicates the motors are not wired properly to the DB9 connectors.

Post the information above and let's see if we can resolve it.

Marty

I have sign of life!!
I tried another DB25, no change. I tried another ethernet cable, no change.
Before seeing Marty's message I wired up a loose stepper motor and it worked with the panel and MIDI.
Then I took the wire cover off of the machine cable and found they used the 5 pin side of the DB9 instead of the G540 required 4 pin side.
Tomorrow is re-solder the connections properly and add the appropriate resistor.
The motors didn't truly lock, but they were very stiff with Acorn / G540 connected.
Famous saying: Trust but verify.
Picture link from earlier is updated with the two different wiring schemes.
Steve.

Sawdust Steve wrote: ↑Wed Feb 23, 2022 6:00 pm I have sign of life!!
I tried another DB25, no change. I tried another ethernet cable, no change.
Before seeing Marty's message I wired up a loose stepper motor and it worked with the panel and MIDI.
Then I took the wire cover off of the machine cable and found they used the 5 pin side of the DB9 instead of the G540 required 4 pin side.
Tomorrow is re-solder the connections properly and add the appropriate resistor.
The motors didn't truly lock, but they were very stiff with Acorn / G540 connected.
Famous saying: Trust but verify.
Picture link from earlier is updated with the two different wiring schemes.
Steve.

Make sure you find the proper coil pairs....
Do you have a spec sheet for the stepper motors on the machine?

Marty

Great news.

[from Marty]
Make sure you find the proper coil pairs....
Do you have a spec sheet for the stepper motors on the machine?
Marty

-=-=-=
I have measured the resistance across pairs at the G540 connector (2.3ohms) to find the coil pairs.
They are 3a and I have 3K ohm set resistors.
No spec sheet, machine only had ~20 hours on it cutting foam for wind tunnel testing at a university lab. New spare steppers came with it.
This is my 3rd build with a G540.
Steve.