G540 Output Only 5V

[shisa7807]

I'm having trouble getting 10V PWM output from G540, Pin 7 (VFD Ground) and Pin 8 (VFD Output). The maximum voltage G540 is outputting is around 5V.

Below are my settings:
VFD = Huayang 2.2kW
Spindle = 2.2kW water cooled, 24,000 rpm.

I'm feeding 10V to G540 from Huayang VFD (also measured 10V). I also have the VFD analog input set to 10V.

Mach 3 RMP Reading	VFD RMP Reading	Voltage Across P7/P8
5,000	10,500	1.9
7,000	11,750	2.6
12,500	15,000	4.6
24,000	16,300	5.6

How do I get G540 to output 10V? How do I get the VFD and Mach 3 rpm to line up?

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[ger21]

What are your pulley speeds?

[shisa7807]

I have the pulley speed set at min 0 rpm and maximum 24,000 rpm to be in line with the spindle rpm.

[shisa7807]

Is the output on G540 P7/P8 digital PWM? If yes, do I need a PWM to analog converter to convert the digital voltage to analog before sending it to the VFD?

My initial though that G540 output would be analog 0-10V, but is this incorrect?

[ger21]

No, it should be converting the PWM signal into a 0-10V output.
But I don't have an answer for what you are seeing.

Is the 10V from the Huanyang constant, even when running?

[shisa7807]

The voltage seems to be constant when measured on a multimeter, but I read an old thread on Mach3 website which said that using on oscilloscope, the 10V from the VFD was noisy. "The +10v reference voltage from the VFD turned out to be the culprit, a cap across the VFD's ground and output cleaned it up nicely."

I don't have an oscilloscope so not sure how to check this. I'm looking around the house for an old power converter to try and switch out the power supply.

[shisa7807]

I couldn't find a 10V DC supply try out, but I found a 50V 22microF capacitor. Connected it across VFD Out and VI and it seems to have done the trick.

On the low to mid range of rpm, the rpm reading in Mach 3 doesn't seem to correlate with the VFD display. Anyone have a theory as to why that it? Am I missing any setting on the VFD or Mach 3?

Below is what I measured also see graph:

VFD Reading (rpm)	Mach 3 Reading (rpm)	Voltage (P7/P8)
10610	5000	2.0
14020	10000	4.1
17464	15000	6.1
20200	19000	7.7
22286	22000	8.9
23590	24000	9.7

[ger21]

If the VFD is seeing 2V, it should not be running at 10,600 rpm. That would be a VFD issue.

[Shadyoak]

Having same problem, was that an Electrolytic cap? which lead is Positive? Thanks