[ZIGGYSCH]

I need to control the revolutions of a small servo. The input will come from 3 to 4 rotary encoders. The servo rpm will be varied depending on the input of the encoders. The maximum rpm of all components will never exceed 20 rpm. Any ideas welcome.

[Al_The_Man]

I assume you intend to switch to different encoders in turn for feedback?
Is this a dedicated or stand alone routine that requires minimum or limited HMI input?
Al.

[ZIGGYSCH]

Hi Al.
Yes; will read one encoder at the time.
The encoder reads the spindle revolutions and starts the movement of the servo at speed 1.
When the encoder has read 20 revolutions it will increase the speed of the servo by 4 times and maintain that speed until the encoder has read an additional 9 revolutions. It will than go back to the original speed 1 and maintain that speed until an additional 5 revolutions are completed.

[Al_The_Man]

I'm a little confused? Your first post mentions 4 separate encoders but the last one talks about increasing the rpm after THE encoder has read *revs?
I just noticed you had posted in the TEKdrive forum as I was going to suggest a Galil solution but if the drives take step/dir input it may not work.
Galil have multi gearing options where you can change the gearing source and ratio from multiple encoder sources on the fly, also Electronic Cam programming.
Al.