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Hi,

i'm trying to control a DC fan which needs a 25 kHz control signal. The control line is connected through the NPN output of an EX-D16A3-TO16 expansion module which is connected to a V1210.

But one thing isn't clear to me at the moment: The expansion module can send a frequency of 1Hz - 32 kHz. So a MI should be enough for the job. But when I look in the help file under "Configuring a High-speed Output (PWM) > Frequency (F)", it says that the Software Units of a V1210 are 0.1Hz (500Hz = 5,000). This would mean that an MI would not be enough because a value of 32,000 would mean I only send a frequency of 3,200 Hz, instead of 32,000 Hz. I cannot select an other operand than a MI, so can I not use this expansion module for sending out an 25kHz signal to my fan?

 

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3 hours ago, thanswijk said:

But when I look in the help file under "Configuring a High-speed Output (PWM) > Frequency (F)", it says that the Software Units of a V1210 are 0.1Hz (500Hz = 5,000).

It says V120, not V1210 in that help entry you're referencing. I think the V120 is an older Vision model, not Enhanced Vision. Have you tried it to see if perhaps it outputs the PWM in units of 1 Hz instead of 0.1 Hz?

@Cara Bereck Levy, does the Help file need to be updated for this function?

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11 minutes ago, Flex727 said:

Have you tried it to see if perhaps it outputs the PWM in units of 1 Hz instead of 0.1 Hz?

Empirical data is the best data.  The spec sheet says the module will go to 32 kHz, so I would hook one up and put a scope on it to verify this.  You can also send an email to support@unitronics.com to get clarification.

Joe T.

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I respectfully disagree with Flex, in that I think thanswijk's interpretation is correct with the software units 0.1Hz, so 500Hz = 5000.  With a Range of 0.1 Hz to 100kHz.

412039915_122917-Jan-1908_21.gif.76f9e8c8074f2cfa02230e95a2a2c345.gif

But as Joe says, the module's HSO frequency is 1-500Hz at PNP, and 1Hz - 32kHz on NPN.  The one thing missing from all the info is how to drive it.  In theory it won't drive with the innate 1210's higher unit.  I tried a quick hardware config in Visi and it brings up an MI for the operand for the module's HSO frequency.  This implies that the module  is driven directly by an MI at 1Hz units, and I'd be going with this.

When I am in doubt, I always do a test bench mockup (as Joe suggests) to find an actual result of something theoretical.

cheers, Aus

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Hi;

 

I got curious and hooked up a IO-D16A3-TO16 and tested the NPN  PWM Output

Frequency   in  MIxx  ( I used MI10)  set to 25,000 Hz.    Duty cycle to 500 (50.0%)

Scope shows a nice  40uS    squarewave   ( 25,000 Hz)     1.2K  load  on NPN Output

      bit of a curve on the rising edge,  sharp  on the falling edge, little bit of jitter

 

Dan

 

 

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Hi guys!
We don't deal with software configuration in the product sheets, only in the Help.

The Help does show the frequency range/units, and does show that you need to link an MI.
Hope this helps :)

hso.png

pwm2.png

 

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Hi Cara;

You point out the PWM  for   Vision PLC's -  PWM is On Board     -- BUT ----

This point here  is for a PWM in an I/O Module   >>   IO-D16A3-TO16   and this is done in 1 Hz increments ( as tested)

                                            also:                                                     >>  EX-D16A3-TO16

                                              also :                                                  >>  EXF-RC15

  An interesting note also about the PWM  in the Expansion --   There is      NO   MB Trigger Bit  Used

 

If these are in HELP  -- let us know where they are.  Search by PWM  does not show them

 

Dan

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Cara, adding to Dan's good explanation, your very first red outline is the crux of the issue.  The modules do not use this rule, so there needs to be specific mention in their manuals of what you link them with.  I could find nothing that says it is a MI.  It is not a huge issue, but the information available is confusing.

cheers, Aus

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I agree with Ausman - this is all very confusing. With the exception of the Standard Vision, V120, an MI will not hold a number large enough to drive the output to the maximum frequency in the spec.

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