Hello experts,

How can I read the encoder to measure motor speed? Do I need special module or I can use normal Digital Input?

Thank you.

regards,

Thank you. I'm gonna use s7 300 series but haven't decided which CPU exactly. I still have no information about the encoder and I should measure the motor speed. 

I need to know what should I consider in order to pick the right CPU.

Thanks

Hello,

If you are going to propose new PLC See the application, S71200 also can read HSC.

And higher range go with onboard HSC as 1511C-1 CPU with display; work memory 175 KB code and 1 MB data; 60 ns bit operation time; 4-level protection concept, integrated technology functions: motion, control, counting & measurement; integrated trace; interface: PROFINET IO controller, supports RT/IRT, 2 ports, I-device,  MRP, transport protocol TCP/IP, S7 communication, Web server, constant bus cycle time, routing; firmware V1.8 with DI16/DQ16, AI5/AQ2 digital input module DI 16xDC24V, grouping 16; digital output module DQ 16xDC24V/0.5A, grouping 16; analog input module AI 4xU/I, AI 1xRTD, 16-bit, grouping 5; analog output module AQ 2xU/I, 16-bit, grouping 2; 6 channels for counting and measurement with incremental encoders 24 V (up to 100 kHz);

Future is S71500 PLC only so better start now.

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Hi William,

Idea for I7 IPC is not bad, but the support for IPC's are too short . Max 5 yrs.. so soft S7500 with IPCs ok..

But think about future and  best optimze solution. So i suggested either S71200 or S71500 compact depends on application size. Any way ,if some one wants to go with Siemens then better go with latest one.

Finally its up to you.