Internet PLC Forum

General => Technical support => Topic started by: Ken Talley on March 09, 2002, 10:58:21 AM

Title: Simultaneous use of one channel
Post by: Ken Talley on March 09, 2002, 10:58:21 AM

Is it possible to use one phycical input by two or more TBASIC functions. For example measure the pulse frequency for PID information and at the same time run a Highspeed counter to function as a totalizer?

Thanks,
Ken

Title: Re: Simultaneous use of one channel
Post by: support on March 10, 2002, 06:39:51 AM

Since the PMON (for pulse measurement) and HSCDEF (high speed counter) share the same input pins, it means that they are mutually exclusive. i.e. if a pin is defind for PMON it cannot be used for HSCDEF. The last defined function prevail.

What you can do is to use input 3,4 as PMON to get two channels of pulse width measurement, then connect a wire from pin 3 to pin 5 and use HSCDEF channel #2 for high speed counter measurement.

Title: Re: Simultaneous use of one channel
Post by: Ken Talley on March 10, 2002, 08:33:21 AM

Would it make the most since to do it as you described or is their an accurate way in programming to totalize using frequency verses time.
Ken ???

Title: Re: Simultaneous use of one channel
Post by: support on March 11, 2002, 09:10:33 AM

I thought the high speed counter alone is sufficient as a "totalizer" if counting pulses is all you need? Why do you need to measure the frequency for totalizing purpose? Anyway, the frequency measurement
is pretty accurate so if you want to use time x frequency the accuracy is determined by how accurate you can capture the time between two measurement.

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