Internet PLC Forum

General => Technical support => Topic started by: improtec on May 12, 2017, 02:16:02 PM

Title: Welding SCR application
Post by: improtec on May 12, 2017, 02:16:02 PM
It is possible to use the PWM outputs to control the firing of the SCR in a Welding resistance spot machine?
Title: Re:Welding SCR application
Post by: support on May 12, 2017, 11:10:10 PM
Unfortunately it is not possible to use PWM to control the firing angle.

To properly control the firing angle you need a zero crossing detection and then compute the time lag until the SCR/TRIAC is fired.

The Fx2424 and Fx1616-BA and any SmartTILE-Fx based custom-made PLC support such built-in capability.

Please refer Chapter 18 (light Dimmer Control) of the Fx2424 User Manual for details.

You can download any user manuals from: http://www.triplc.com/documentations.htm

Thank you.
Title: Re:Welding SCR application
Post by: improtec on June 11, 2017, 06:22:21 AM
Unfortunately it is not possible to use PWM to control the firing angle.

To properly control the firing angle you need a zero crossing detection and then compute the time lag until the SCR/TRIAC is fired.

The Fx2424 and Fx1616-BA and any SmartTILE-Fx based custom-made PLC support such built-in capability.

Please refer Chapter 18 (light Dimmer Control) of the Fx2424 User Manual for details.

You can download any user manuals from: http://www.triplc.com/documentations.htm

Thank you.



The FXs have special functions to do it, using the interrupts input, It is possible to do it with the Nano? I mean using the interrupt input and do by programming Zero cross detection?

Thank you
Title: Re:Welding SCR application
Post by: support on June 12, 2017, 10:15:38 AM
Sorry that is not supported on Nano-10 or FMD.  The phase-cut is supported in firmware of Fx CPU but there is not enough resources on the Nano-10 and FMD PLCs to support this function.