# Action Pak 7510-6001-2 Frequency Divider/ Scaler Edit Subject

Hi we recently bought two Action Pak 7510-6001-2 Frequency Divider Scalers from you.

We are using them to divide down the frequency of a 1000 Pulse per turn rotary pulse encoder. The encoder runs at a maximum speed of 1000 RPM. We are trying to limit the frequency to less than 2kHz using the 7510.

The problem we are seeing is with a 24V square wave from the pulse encoder (for example 100uS low 100uS high) connected to the 7510 we are getting an output that is high for 2ms and low for 100uS. When the multiplication factor is 0.10000

We are using output (9) with a 1.2kOhm pull-up to 24V.

We were expecting a square wave output of say 1ms high and 1mS low. The output signal is then connected to a motion detector which should stop the operator from opening the machine if it detects motion above a certain speed.

Why is the 7510 not dividing down the frequency and keeping the mark space ratio approximately constant ?

The problem is the motion detector sees the signal as high all the time the 100uS low seems to be too short to detect.

How can we change the 7510 to give us a square wave output (a lower frequency version of the square wave input) ?

My contact details:-
Val Rendle
Drives & Controls NZ Ltd
val@dcnz.com
Tel (DDI) +64-9-921-0373
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• Hello Val Rendle,

Is it dividing the frequency, but not maintaining a 50% duty cycle?
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• Hi Tom,

Yes, it divides the input square wave frequency but does not maintain the input duty cycle.

How can we achieve a similar square wave on the output but at a lower frequency ?
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• Hi Val,

What you are seeing is correct.
The 7510 does not output a 50% duty cycle when using a scaling factor.
The 7510 removes pulses from the output similar to the below.

If you need a 50% duty cycle I’m going to suggest the Q498-0000. The Q498 can take a frequency input and output a frequency with a 50% cycle. It has a soft pull up to 18V @ 1mA so it’s basically an open collector output. You would also need the C698-0000 cable and software to program. The Q498 is 24V DC powered.
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• Hi Larry,

Thanks for the clarification. I accept that it is working as designed but the data sheet did not make it clear that it removes pulses from the input and therefore does not maintain the input waveform.

We will either try the Q498 or make something based on a couple of 4013 D-Type Flip Flops. With 4 flip flops cascaded we can divide the input square wave down by 2, 4, 8 or 16 times. We were looking to divide by 10, but a divide by 16 will be OK.

Val
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