SM321 - Encoder Inputs

I have selected following hardware fr my project. 

I have a encoder with 250 PPR(pulse per revolution)

From the hardware given below please tell me if I can connect my encoder to the input module or not. 

I have read few threads in forum but none is exactly related to my problem.

CPU 319-3 PN/DP

Input module -  SM 321 - 16 DI - MLFB - 6ES7321-1BH02-0AA0

I hope this information is enough, if more information required feel free to ask. 

yes, you can connect it.

But i think it will not work, except very slow rotations.

Do you use a drive for your motor? What is the application?

Yes I am using a drive for it, which has CU 250 s 

I want to count the length of the winding material, so I am using a encoder. Speed wont exceed more than 100 rpm

100 rpm *250 ppr=  25000 pulses per minute

25000/60 = 417 pulses per second

i think thats to fast for simatic s7-300.

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You should connect your Encoder to your drive.

Have a look at: https://support.industry.siemens.com/cs/de/en/view/78794884 (page 66)

Again:

Yes you could connect your Encoder to Standard Inputs, but probably it will not work.

417 pulses per second mean that every 2,4 ms a pulse have to be processed. A simatic s7-300 plc is not made for this.

An encoder is drive-related and should be connected to the drive, please please look at the manual I sent you last time