Read up on what reference voltage is.
(Or read Peter¡¯s post again ¨C he tells you.)
From: mach1mach2cnc@... [mailto:mach1mach2cnc@...]
Sent: Wednesday, 11 March 2015 4:32 PM
To: mach1mach2cnc@...
Subject: RE: [mach1mach2cnc] VFD and PWM and G540
Peter:
Did you just go over the top 10 volt DC will kill you. The pin our isolated (7&9) on 540 as we know it. I let you know if I blow something up
Good trying
C
From: mach1mach2cnc@... [mailto:mach1mach2cnc@...]
Sent: Tuesday, March 10, 2015 9:49 PM
To: mach1mach2cnc@...
Subject: RE: [mach1mach2cnc] VFD and PWM and G540
Hi,
Without exception (from my experience to date ) all VFD's have a 10Vdc supply that is used as a power supply for attaching a manual speed potentiometer. This 10V supply is used to provide power to the G540 VFD pins 7 and 9.
If you are controlling a DC motor controller that does not provide such a supply you will need to use an auxillary dc power supply of a voltage that suits you spindle speed controller's input specification.
NOTE: This auxillary supply NEEDS TO BE AN ISOLATED SUPPLY!!!! as the 0v reference for this supply may be near main potential voltage. 110/220V. If you don't use an isolated supply you may end up destroying your motor controler, cnc controller, PC and yourself.
If you don't understant the above then DON'T attempt to wire it up as the voltages involved may kill you. Also, any work involved with Mains Voltage needs to be done by a qualified electrician.
Cheers,
Peter
-------------------------
Peter Homann
On Wed 11/03/15 9:15 AM , "Chris microcnc_31@... [mach1mach2cnc]" <mach1mach2cnc@...> wrote:
Excellent, what type of power supply can I use for this as it appears a
second power supply is required
Thanks
Chris
-----Original Message-----
From: mach1mach2cnc@... [mach1mach2cnc@...]
Sent: Tuesday, March 10, 2015 1:59 PM
To: mach1mach2cnc@...
Subject: Re: [mach1mach2cnc] VFD and PWM and G540
Hi,
No, the G540 pins 7 and 9 do not output a 12V supply on their own.
The G540 generates an isolated control voltage on pin 8. The amplitude of
the voltage is voltage is a percentage of the voltage that is supplied to
pins 7,8 of the G540. The percentage is derived from the Mark/space ratio of
the PWM signal from Mach3 that is present of pin 14 of the G540's DB25
connector.
So, if the duty cycle (mark/space) ratio is 25%, then the voltage output on
pin 8 of the terminal block will be 25% of the voltage you supply across
pins 7,9. In this example, if you supply pins 7 and 9 with 10V, the G540
will generate 2.5V on pin 8.
If you supply pins 7 and 9 with 12V, the G450 will generates 3V on pin 8
when
Mach3 outputs a PWM with a duty cycle of 25%
Note, the recommended max voltage supply across pins 7,9 is 12Vdc.
Cheers,
Peter
On 11/03/2015 3:48 AM, Chris microcnc_31@... [mach1mach2cnc] wrote:
Hello:
Can anyone tell me how the PWM signal comes out of Mach?. And if you
have made connection correctly from G540?. Pin 7,8 and 9 are connected
to VFD, Does pin
7 and 9 put out 12V on their own?
Thanks
Chris
