G540 - 4 motor connection problem

[Clive S]

Why would a retailer bundle kits that don't work together - all of them have less power than required?

This is exactly the reason that we generally always inform new members never to buy any kits of parts as they are rarely matched

[m_c]

That size power supply should be fine. As these are modern chopper style drives, they won't actually draw the full 3.5A from the power supply unless you are really pushing all the motors hard at speed, which is quite unlikely.

It could however be a problem with the power supply. Ideally I'd connect an oscilloscope over the power supply, and see what is happening with all the motors connected.
You may be able to catch any dip in voltage with a voltmeter, as the dip would likely have to last for a second or two for the drive voltage to drop low enough to cause problems.
Does the power supply have any kind of voltage OK output? it may be worth connecting up a lamp to see if the power supply is shutting down when the problem happens.

[Neale]

As Clive says, the kits are often put together using less than ideal choices of components. In this case, I would guess that the kit uses a switch-mode power supply because these are smaller, lighter, and in particular cheaper than a linear supply, which is the preferred option from a purely technical viewpoint. The linear supply can cope with peak overload without breaking into a sweat where the SMPS can trip internal overload protection. I'm a bit surprised as well that there is a problem, though, but seeing that it appears to be load-related, and is a bit variable suggesting that perhaps it is when all motors are trying to deliver pulses simultaneously which won't happen all the time, maybe it is the PSU. Does seem on the face of it to be the most likely issue. My own machine uses small, cheap SMPS boxes for control circuitry where the load is smaller and well-defined (very cost-effective here) but I use a linear supply for the stepper drivers.

[Clive S]

If I am not mistaken depending on the how the drives are set the motors will draw more current when stationary

[m_c]

I would expect the internal filtering capacitors of the Gecko drives to minimise any harmonics that could cause high instantaneous current use.

However, what I'm wondering is what is the actual fault being caused?

[komatias]

With the 3.5A tuning and your power supply the gecko should work 100% fine. I suspect there is something tripping the chargepump.

What are you using to drive the Gecko? parallel port? Is that conking out and causing the chargepump to go low?

[dachopper]

This is my power supply http://www.automationtechnologiesinc...upply/48v12-5a

I have the G540, connected with the DSUB ribbon to UC400ETH controller, then that goes Cat5 cable to a switch, and cat5 to my laptop.

When the fault occurs, the connection between the UC400ETH and Laptop and UCCNC program looks normal ( the G540 disables the servo's from moving, and the UCCNC software shows that the motors are still being told to move without any limit switch activation.
)

I noticed aswell, a little noise from the servo's when they are stationary and they are all connected, but less when there are 1 or 2 or 3 motors connected is this normal?

I've checked the resistors and they are 100% correctly installed, and re-wired the power supply to G5540 + and - with other 14G braded wire last night

[dachopper]

Another thought

To troubleshoot the power supply, I have a Mastech 30 Volt 10 Amp variable DC switching power supply.

Should I plug this in ( although it's only 30 volts, and the other one is 48 volts ) and see if there is a difference?

Nick