Resistor value and tolerance question for G540 and steppers

[Stevenh111]

According to the g540 manual my resistors for the motors should be 6.1k for the nema 34 on the z axis and 3.5k for the nema 23 on the x&y. These are the resistors that connect pins 5 & 1 on the db9 between the g540 and the stepper motors.

The closest I have is a 6.7k and. 3.3 k both 5% tolerance. Are these values ok to allow my motors to run and still have a standby?

Thanks in advance for any information

[cornbinder23]

You will need 3.5K for the Z as well, not 6.1
On mine I used 1-3.3k and 2-100ohm resistors in series to get the correct resistance value.
But then I bought the EZG540's and just dialed them in
I am no expert on stepper controllers but IIRC the current limiting resistor is for the controller to go into idle current reduction mode and not let the steppers sit there heating up.

JTCUSTOMS

[Stevenh111]

Thanks for your answer.

The reason I figured a 6.1k for the z is that it is a larger motor and if I am correctly reading the spec sheet from keling it has a current draw of 6.1 amps in parallel wiring so that current draw x 1000 according to the G540 manual is what I need?

I didn't know if I could for 3resistors in parallel insode of the connector case so I decided to use a small 10k ceramic potentiometer on the outside of the d9 connector and set it for the correct value.

My G540 from keling has some trim pots next to the connectors on the panel that gecko says are for low speed smoothing. I am assuming that these are different from the trim pots you are speaking of on the EZG540?

I am slowly making my way towards cnc on this. You a folks are a tremendous help!

Thanks

[john_100]

Hi stevenh111

the G540's maximum current is 3.5A
with a current setting resistor over 3k5 (3500 ohms) the G540 will not go into standby

the resistor in ohms is the motor current in amps x 1000

if you use a single resistor or two in series ,so you only have to solder one wire into
each of the terminals on the D type connector

the diagram gives just a few of the many possible resistors from the E12 , E 24 and E48 series of prefered values

in the manual , the resistors need only be to + or - 5%

a 3500 ohm resistor + or - 5% could be from 3325 ohms to 3675 ohms

using a 3300 ohm and 220 ohm resistor in series to make 3520 ohms is not a problem

John

[cornbinder23]

I fit all the resistors in the backshell no problem at all, plenty of room in there.
Sooooo according to jon_100 I did recall correctly

JTCUSTOMS

[Scuba Steve]

stevev i took Corndinders advise and ordered a set of the 540ez. only took a few days to get here and they are alot esier to solder to as i think u have 18 ga like i used. soigeneris is the place where i got mine.
thoso other holes you were asking about is a final adjuster for each motor to smoth them out.
Steve

[Stevenh111]

Thanks cornbinder, john and steve. I just found your reply Steve. After reading Cornbinders reply I wound up ordering the 540ez last night from Soigeneris. Much neater and probably more reliable than what I came up with.

Lastly, I called Gecko to get a final judgment on resistor values for larger Z axis stepper and found out some new information to me at least. Their tech recommended that I run the Z stepper in series not parallel. He said that series has a bum rap. I gave him the inductance for my particular motor and he saidmitmwould work fine. That way since the current draw is only 3.1 A instead of 6.1A in parallel I would use only a 3.1k value one the Z and get better torque.

The 3.5K value for the X & Y are obviously still correct since I will run them in parallel.

Steven

stevev i took Corndinders advise and ordered a set of the 540ez. only took a few days to get here and they are alot esier to solder to as i think u have 18 ga like i used. soigeneris is the place where i got mine.
thoso other holes you were asking about is a final adjuster for each motor to smoth them out.
Steve