Rate Measurement - 1769HSC

Regarding the rate measurement capability of the Allen-Bradley 1769HSC - according to the datasheet, it can handle up to "4 channels of pulse/count inputs", but it is not clear on exactly the operation mode of these inputs.

I require 4 channels of frequency measurement of pulse input (single direction only). Is the HSC capable of this?

It would also be desirable to get a counter reading as well as a rate measurement for each input. Is this also possible?

Thanks in advance

Simple answer is that it records counts, you use those counts versus time to get what you need.

Go to pages 2-18 up to 2-21 of Publication 1769-UM006A-EN-P and you will find the answers to your questions, you can download it from AB web page.

It seems to me as though the counts and rates are stored in different registers; Local:<x>:I.Ctr<y>CurrentCount and Local:<x>:I.Ctr<y>CurrentRate respectively.

One reason I ask this question is that other brands, Telemecanique for example, allow four pulse inputs in counting mode, but when those same inputs are used in rate measurement mode the number of inputs drops to two. Further, a frequency meter can not give a total count value, and a counter can not give a rate value.

When the 1769HSC is used in RATE mode, are all four inputs still available? And, though not absolutely necessary, can the total counts be read directly from the register also?

Thanks widelto,

I do not quite understand what the user manual is saying though. It seems to me that what I want to do is possible; I would just like some confirmation!

Yes, it is possible, and those counters can have independent rate mode update times as well. (slot:C.Ctr<#>CyclicRateUpdateTime)

But, of course, that is on a Logix platform. What platform are you using?

Thanks for your help mate. Yes, it will be a CompactLogix platform.