Internet PLC Forum

General => Technical support => Topic started by: CMS on May 07, 2007, 09:03:18 PM

Title: 8 VOLT PWM SIGNAL
Post by: CMS on May 07, 2007, 09:03:18 PM

Hi

Can the T100MX ( opto inputs ) handle a 8 Volt PWM signal at 500 hz.      Is the 8 volt enought to trigger the input??

Thankyou

Title: Re:8 VOLT PWM SIGNAL
Post by: support on May 08, 2007, 07:23:11 AM

The spec is 9V minimum but 8 volt could be just about sufficient to turn on the T100MX+ optoisolated inputs. In the worst case scenario you can solder in parallel a resistor to the current limiting resistor onboard the PLC to increase the sensitivities.

500  Hz PWM signal is not a problem. You can use the PULSEWIDTH and PULSEPERIOD function to accurately measure the duty cycle of the PWM inputs.

Title: Re:8 VOLT PWM SIGNAL
Post by: Dogface on May 08, 2007, 07:38:51 AM

Another alternative is to use a high speed switching transistor.

8volt signal through a 500KOhm resistor into the base.  Collector tied into the PLC input. The emitter tied into ground.

Works like a charm.