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General => Technical support => Topic started by: DAlgie on November 10, 2011, 06:58:33 PM

Title: Pulse width
Post by: DAlgie on November 10, 2011, 06:58:33 PM

Hi, I am trying to output a varying pulse width signal. I need it to be between 1ms and 2ms, in tenths of a ms. This is from a FMD1616. I read all the literature and is is unclear if this is possible. The older TMD 1616 had only a certain amount of fixed pulse frequencies I believe.

Title: Re:Pulse width
Post by: support on November 11, 2011, 01:12:13 AM

Yes, you can use the SETPWM command to set the duty cycle and the frequency of a PWM output. For FMD PLC the frequency is continuously variable between 50Hz and 50KHz so you can create a wave form with very accurate frequency/period, and you can compute the duty cycle required to generate the pulsewidth of your choice.

Are you trying to control a RC Servo with 1ms to 2ms signal? Section 11.4 in the FMD PLC User's Manual Section describes how this can be achieved.

Title: Re:Pulse width
Post by: DAlgie on November 11, 2011, 05:57:36 AM

Yes, that's it exactly, need to control a number of RC servos (among other things). PAGE 11.4 of the users manual (the book)only shows For...Next statements, which users manual do you mean?

Title: Re:Pulse width
Post by: support on November 11, 2011, 08:37:21 AM

http://www.tri-plc.com/documents/FMD1616-10-UserManual.pdf

Title: Re:Pulse width
Post by: DAlgie on November 11, 2011, 11:28:11 AM

Thank you, that is it exactly.