Internet PLC Forum

General => Technical support => Topic started by: can on August 23, 2010, 01:06:28 AM

Title: Signal Reading
Post by: can on August 23, 2010, 01:06:28 AM

Hi. I have a motor driver that output TTL 4096 signal. Can I use it to calculate the number of revolution the motor has rotated?

Thank you.

Title: Re:Signal Reading
Post by: support on August 23, 2010, 10:13:38 AM

what do you mean by TTL4096 signal? TTL is digital logic voltage, which means 0 to approx 1 volt is logic 0, +2.5 to +5V is logic 1. The number 4096 suggest that it is either a 12-bit analog or PWM or frequency output. How to interface depending on what it is.

Title: Re:Signal Reading
Post by: can on September 23, 2010, 07:08:20 AM

Hi. Actually I'm trying to determine the number of revolutions by using the A and B signal from a 5v encoder. Can 888 determine the number of revolution using the signal? Thank you

Title: Re:Signal Reading
Post by: support on September 23, 2010, 08:37:58 AM

You need an interface to convert the TTL signal to NPN output. A ULN2003A will do the trick. Please read the PLC's User's Manual - there is description on the wiring method there.

Title: Re:Signal Reading
Post by: can on September 28, 2010, 07:57:00 PM

Hi. I've seen the diagram on using the UN2003A. Just want to make sure something. Do I connect the 0V from the encoder output, pin 8 and PLC 0V together even though the encoder is drawing from it's own power supply while the PLC is drawing from another power supply?

Thank you.

Title: Re:Signal Reading
Post by: support on September 28, 2010, 09:53:27 PM

Yes, if the PLC and encoder and using different power supply then you need to connect their 0V together to provide a common reference.