Pulse output to analog input?

Hello to all! I'm hoping that someone here can point me in the right direction. I am working on a project involving the use of a motor and I wanted to add a rotary encoder (incremental) to the set up. Most of the encoders I've looked at give an output in pulses per second.
I want the encoder to output an analog voltage signal that would connect to an analog input on a PLC. Am I correct in believing that a pulse output (from the encoder) will not work on an analog input (to the PLC)???

Am I correct in believing that a pulse output (from the encoder) will not work on an analog input (to the PLC)???

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That is correct. Assuming the pulsed signal is 50% duty cycle, you'd just see a constant voltage equal to half of the encoder output voltage, regardless of speed.

There are signal conditioners available that convert a pulsed signal to an analog voltage signal. A few examples:
http://www.redlion.net/Products/ProcessControl/SignalConditioning/FrequencyInputs.html

A preferable solution would be to send the encoder directly into a high-speed input on your PLC. Eliminate the middleman. Depends on your available hardware of course... what PLC are you using?

Depending on what PLC you are using, the correct way to connect an encoder to a PLC is by using a high speed counter. Look and see if your PLC has this option available.

I'm using a Siemens S7 1200. It has high speed counters which could count the pulses but I was really hoping to use the analog input. I'm sure I can find an encoder that outputs an analog signal. Thanks for your reply.

paulie walnuts said:

I want the encoder to output an analog voltage signal that would connect to an analog input on a PLC.

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You want a tacho, not an encoder.

a cheap solution is with a 555 timer.
as you have high speed counters just time the overflow and you will have a speed.